Background:LL-37 peptide is a member of the human cathelicidin family,and has been shown to promote the healing of pressure ulcers.However,the low stability of this peptide within the wound environment limits its clin...Background:LL-37 peptide is a member of the human cathelicidin family,and has been shown to promote the healing of pressure ulcers.However,the low stability of this peptide within the wound environment limits its clinical use.Chitosan(CS)hydrogel is commonly used as a base material for wound dressing material.Methods:CS hydrogel(2.5%w/v)was encapsulated with LL-37.Cytotoxicity of the product was examined in cultured NIH3 T3 fibroblasts.Effects on immune response was examined by measuring tumor necrosis factor-α(TNF-α)release from RAW 264.7 macrophages upon exposure to lipopolysaccharides.Antibacterial activity was assessed using Staphylococcus aureus.Potential effect on pressure ulcers was examined using a mouse model.Briefly,adult male C57 BL/6 mice were subjected to skin pressure using magnets under a 12/12 h schedule for 21 days.Mice were randomized to receive naked LL-37(20μg),chitosan gel containing 20μg LL-37(LL-37/CS hydrogel)or hydrogel alone under the ulcer bed(n=6).A group of mice receiving no intervention was also included as a control.Results:LL-37/CS hydrogel did not affect NIH3 T3 cell viability.At a concentration of 1–5μg/ml,LL-37/CS inhibited TNF-αrelease from macrophage.At 5μg/ml,LL-37/CS inhibited the growth of Staphylococcus aureus.The area of the pressure ulcers was significantly lower in mice receiving LL-37/CS hydrogel in comparison to all other 3 groups on days 11(84.24%±0.25%),13(56.22%±3.91%)and 15(48.12%±0.28%).Histological examination on days 15 and 21 showed increased epithelial thickness and density of newly-formed capillary with naked LL-37 and more so with LL-37/CS.The expression of key macromolecules in the process of angiogenesis(i.e.,hypoxia inducible factor-1α(HIF-1α)and vascular endothelial growth factor-A(VEGF-A))in wound tissue was increased at both the mRNA and protein levels.Conclusion:Chitosan hydrogel encapsulated with LL-37 is biocompatible and could promote the healing of pressure ulcers.展开更多
Two-photon microscopy normally suffers from the scattering of the tissue in biological imaging.Multidither coberent optical adaptive technique(COAT)can correct the scattered wavefront in parallel.However,the determina...Two-photon microscopy normally suffers from the scattering of the tissue in biological imaging.Multidither coberent optical adaptive technique(COAT)can correct the scattered wavefront in parallel.However,the determination of the corrective phases may not be completely accurate using conventional method,which undermines the performance of this technique.In this paper,we theoretically demonstrate a method that can obtain more accurate corrective phases by determining the phase values from the square root of the fuorescence signal.A numnerical simulation model is established to study the performance of adaptive optics in two-photon micros-copy by combining scalar diffraction theory with vector diffraction theory.The results show that the distortion of the wavefront can be corrected more thoroughly with our method in two-photon imaging.In our simulation,with the scattering from a 450-mn-thick mouse brain tissue,excitation focal spots with higher peak-to background ratio(PBR)and images with higher contrast can be obtained.Hence,further enhancement of the multidither COAT correction performance in two-photon imaging can be expected.展开更多
Structured illumination microscopy(SIM)is an established optical superresolution imaging technique.However,conventional SIM based on wide-field image acquisition is generally limited to visualizing thin cellular sampl...Structured illumination microscopy(SIM)is an established optical superresolution imaging technique.However,conventional SIM based on wide-field image acquisition is generally limited to visualizing thin cellular samples.We propose combining one-dimensional image rescan and structured illumination in the orthogonal direction to achieve superresolution without the need to rotate the illumination pattern.The image acquisition speed is consequently improved threefold,which is also beneficial for minimizing photobleaching and phototoxicity.Optical sectioning in thick biological tissue is enhanced by including a confocal slit in the system to significantly suppress the out-of-focus background and the associated noise.With all the technical improvements,our method captures threedimensional superresolved image stacks of neuronal structures in mouse brain tissue samples for a depth range of more than 200μm.展开更多
Treatment-induced apoptosis of cancer cells is one goal of cancer therapy.Interestingly,more heat is generated by mitochondria during apoptosis,especially the uncoupled apoptotic state,^(1,2) compared to the resting s...Treatment-induced apoptosis of cancer cells is one goal of cancer therapy.Interestingly,more heat is generated by mitochondria during apoptosis,especially the uncoupled apoptotic state,^(1,2) compared to the resting state.In this case study,we explore these thermal effects by longitudinally measuring temperature variations in a breast lesion of a pathological complete responder during neoadjuvant chemotherapy(NAC).Diffuse Optical Spectroscopic Imaging(DOSI)was employed to derive absolute deep tissue temperature using subtle spectral features of the water peak at 975 nm.^(3)A significant temperature increase was observed in time windows during the anthracycline and cyclophosphamide(AC)regimen but not in the paclitaxel and bevacizumab regimen.Hemoglobin concentration changes generally did not follow temperature,suggesting the measured temperature increases were likely due to mitochondrial uncoupling rather than a direct vascular effect.A simultaneous increase of tissue oxygen saturation with temperature was observed,suggesting that oxidative stress also contributes to apoptosis.Although preliminary,this study indicates longitudinal DOSI tissue temperature monitoring provides information that can improve our understanding of the mechanisms of tissue response during NAC.展开更多
We have developed a two-photon fluorescence microscope capable of imaging up to 4mm inturbid media with micron resolution.The key feature of this instrument is the innovative de-tector,capable of collecting emission p...We have developed a two-photon fluorescence microscope capable of imaging up to 4mm inturbid media with micron resolution.The key feature of this instrument is the innovative de-tector,capable of collecting emission photons from a wider surface area of the sample thandetectors in traditional two-photon microscopes.This detection scheme is extremely efficient inthe collection of emitted photons scattered by turbid media which allows eight fold increase in theimaging depth when compared with conventional two-photon microscopes.Furthermore,thissystem also has in-depth fluorescence lifetime imaging microscopy(FLiM)imaging capabilitywhich increases image contrast.The detection scheme captures emission light in a transmissionconfiguration,making it extremely efficient for the detection of second harmonic generation(SHG)signals,which is generally forward propagating.Here we present imaging experiments oftissue phantoms and in vivo and ea vivo biological tissue performed with this microscope.展开更多
Deep tissue pressure injuries(DTPIs)have witnessed a growing prevalence in hospitals and other health care units especially among individuals with pathological conditions that give rise to restricted mobility,impaired...Deep tissue pressure injuries(DTPIs)have witnessed a growing prevalence in hospitals and other health care units especially among individuals with pathological conditions that give rise to restricted mobility,impaired sensation,and reduced tissue tolerance.The etiology of DTPIs has been a subject of controversy,to which several explanatory models have been proposed,including direct mechanical insult,ischemia-reperfusion,lymphatic occlusion,and inflammatory cytokines.In line with these pathophysiological scenarios,ultrasound,subepidermal moisture detection,and biomarker technologies have been proposed as potential early detection methods of DTPIs.This paper provides a systematic review involving these three methods.The conclusion is that combining and implementing these methods at different time periods during DTPIs development and progression respectively is likely to be the most universal,effective and promising way for DTPIs diagnosis.展开更多
Objective:analyze and discuss the clinical application of thermal therapy for deep tissue tumor in medical oncology. Methods: 54 patients admitted to the Department of Oncology of our hospital during September 2017 to...Objective:analyze and discuss the clinical application of thermal therapy for deep tissue tumor in medical oncology. Methods: 54 patients admitted to the Department of Oncology of our hospital during September 2017 to June 2018 were selected as the research subjects. Combined with their admission order, they were divided into two groups. 27 patients with double number were divided into the control group, who only received radiotherapy. 27 patients with single number were divided in the study group and received thermal therapy for deep tissue tumor, and the clinical application effect of different treatment regimens in the two groups was compared. Results: the effective rate of the study group was relatively higher than that of the control group (P<0.05). Conclusion: patients have thermal therapy for deep tissue tumor in medical oncology has higher clinical efficacy and better disease control effect, with relatively high safety, feasibility and worth promoting vigorously.展开更多
Lanthanide(Ln^(3+))-doped luminescent nanocrystals(NCs)with excitation and emission in the second near-infrared biological window(NIRII,1000-1700 nm)have attracted considerable attention in the fields of deep-tissue b...Lanthanide(Ln^(3+))-doped luminescent nanocrystals(NCs)with excitation and emission in the second near-infrared biological window(NIRII,1000-1700 nm)have attracted considerable attention in the fields of deep-tissue bioimaging and non-invasive biodetection,owing to their superior advantages including good photochemical stability,sharp emission peaks,large penetration depth,and high signal-to-noise ratio[1].Conventionally,Yb3t-and Nd3t-sensitized NCs have been utilized as NIR-II luminescent nanoprobes for in vivo bioimaging upon excitation with 980 and 808 nm diode laser,respectively[2].展开更多
Fluorescence imaging is a noninvasive and dynamic real-time imaging technique;however,it exhibits poor spatial resolution in centimeter-deep tissues because biological tissues are highly scattering media for optical r...Fluorescence imaging is a noninvasive and dynamic real-time imaging technique;however,it exhibits poor spatial resolution in centimeter-deep tissues because biological tissues are highly scattering media for optical radiation.The recently developed ultrasound-controlled fluorescence(UCF)imaging is a novel imaging technique that can overcome this bottleneck.Previous studies suggest that the effective contrast agent and sensitive imaging system are the two pivotal factors for generating high-resolution UCF images ex vivo and/or in vivo.Here,this review highlights the recent advances(2015e2020)in the design and synthesis of contrast agents and the improvement of imaging systems to realize high-resolution UCF imaging of deep tissues.The imaging performances of various UCF systems,including the signal-to-noise ratio,imaging resolution,and imaging depth,are specifically discussed.In addition,the challenges and prospects are highlighted.With continuously increasing research interest in this field and emerging multidisciplinary applications,UCF imaging with higher spatial resolution and larger imaging depth may be developed shortly,which is expected to have a far-reaching impact on disease surveillance and/or therapy.展开更多
We report a novel stimulated Raman scattering(SRS)microscopy technique featuring phase-controlled light focusing and aberration corrections for rapid,deep tissue 3D chemical imaging with subcellular resolution.To acco...We report a novel stimulated Raman scattering(SRS)microscopy technique featuring phase-controlled light focusing and aberration corrections for rapid,deep tissue 3D chemical imaging with subcellular resolution.To accomplish phasecontrolled SRS(PC-SRS),we utilize a single spatial light modulator to electronically tune the axial positioning of both the shortened-length Bessel pump and the focused Gaussian Stokes beams,enabling z-scanning-free optical sectioning in the sample.By incorporating Zernike polynomials into the phase patterns,we simultaneously correct the system aberrations at two separate wavelengths(~240 nm difference),achieving a~3-fold enhancement in signal-to-noise ratio over the uncorrected imaging system.PC-SRS provides>2-fold improvement in imaging depth in various samples(e.g.,polystyrene bead phantoms,porcine brain tissue)as well as achieves SRS 3D imaging speed of~13 Hz per volume for real-time monitoring of Brownian motion of polymer beads in water,superior to conventional point-scanning SRS 3D imaging.We further utilize PC-SRS to observe the metabolic activities of the entire tumor liver in living zebrafish in cellsilent region,unraveling the upregulated metabolism in liver tumor compared to normal liver.This work shows that PCSRS provides unprecedented insights into morpho-chemistry,metabolic and dynamic functioning of live cells and tissue in real-time at the subcellular level.展开更多
Optical imaging plays an important role in biomedical research being extremely useful for early detection, screening and image-guided therapy. Lanthanide-doped up-converting nanoparticles were ideally suited for bioim...Optical imaging plays an important role in biomedical research being extremely useful for early detection, screening and image-guided therapy. Lanthanide-doped up-converting nanoparticles were ideally suited for bioimaging because they could be ex- cited in near infrared （NIR） and emit in NIR or visible （VIS）. Here, we compared lanthanide doped up-converting NaYF4 and organic fluorophores for application in deep-tissue imaging. For that purpose - tissue phantoms mimicking the natural properties of light scat- tering by living tissues were prepared. The studies allowed to quantitatively compare optical resolution of different fluorescent com- pounds, revealing that the NIR photoexcitation was favorable over conventional UV photoexcitation.展开更多
It is very challenging to visualize implantable medical devices made of biodegradable polymers in deep tissues.Herein,we designed a novel macromolecular contrast agent with ultrahigh radiopacity(iodinate content>50...It is very challenging to visualize implantable medical devices made of biodegradable polymers in deep tissues.Herein,we designed a novel macromolecular contrast agent with ultrahigh radiopacity(iodinate content>50%)via polymerizing an iodinated trimethylene carbonate monomer into the two ends of poly(ethylene glycol)(PEG).A set of thermosensitive and biodegradable polyester-PEG-polyester triblock copolymers with varied polyester compositions synthesized by us,which were soluble in water at room temperature and could spontaneously form hydrogels at body temperature,were selected as the demonstration materials.The addition of macromolecular contrast agent did not obviously compromise the injectability and thermogelation properties of polymeric hydrogels,but conferred them with excellent X-ray opacity,enabling visualization of the hydrogels at clinically relevant depths through X-ray fluoroscopy or Micro-CT.In a mouse model,the 3D morphology of the radiopaque hydrogels after injection into different target sites was visible using Micro-CT imaging,and their injection volume could be accurately obtained.Furthermore,the subcutaneous degradation process of a radiopaque hydrogel could be non-invasively monitored in a real-time and quantitative manner.In particular,the corrected degradation curve based on Micro-CT imaging well matched with the degradation profile of virgin polymer hydrogel determined by the gravimetric method.These findings indicate that the macromolecular contrast agent has good universality for the construction of various radiopaque polymer hydrogels,and can nondestructively trace and quantify their degradation in vivo.Meanwhile,the present methodology developed by us affords a platform technology for deep tissue imaging of polymeric materials.展开更多
Fluorescence imaging has become an essential tool in biomedical research.However,non-invasive deep-tissue threedimensional optical in vivo imaging with the high spatiotemporal resolution is challenging due to the inte...Fluorescence imaging has become an essential tool in biomedical research.However,non-invasive deep-tissue threedimensional optical in vivo imaging with the high spatiotemporal resolution is challenging due to the interaction between photons and tissues.Beam shaping has been used to tailor microscopy techniques to enhance microscope performance.The nearinfrared window(NIR)between 700 and 1,700 nm,generally emphasized as the NIR-II(1,000–1,700 nm)window,has been developed into a promising bio-optical solution chosen as the lower interaction effect in this spectrum,showing potential in basic biological research and clinical application.In this review,we summarize the existing methods to increase penetration depth and extensively describe biological microscopy techniques,NIR-II spectral windows,and fluorophores.Strategies to improve bioimaging performance and NIR-II imaging applications are introduced.Based on the current research achievements,we elucidate the main challenges and provide some recommendations and prospects for deep tissue penetration fluorescence for future biomedical applications.展开更多
Measurement of light distribution in biological tissue contributes to selecting strategy and optimizing dose for biomedical application. In this letter, a photoacoustic method combined with Monte Carlo simulation was ...Measurement of light distribution in biological tissue contributes to selecting strategy and optimizing dose for biomedical application. In this letter, a photoacoustic method combined with Monte Carlo simulation was used to estimate the three-dimensional light distribution in biological tissue. The light distribution was produced by a cylindrical diffuser which interposed into tissues. The light profiles obtained by the method were compared to those detected by photo diodes. The experimental results demonstrate the feasibility of this method. The approach can play a significant role for photo-dosimetry in biomedical phototherapy.展开更多
Under some circumstances surgical resection is feasible in a low percentage for the treatment of deep tumors. Nevertheless, high-intensity focused ultrasound （HIFU） is beginning to offer a potential noninvasive alte...Under some circumstances surgical resection is feasible in a low percentage for the treatment of deep tumors. Nevertheless, high-intensity focused ultrasound （HIFU） is beginning to offer a potential noninvasive alternative to conventional therapies for the treatment of deep tumors. In our previous study, a large scale spherical HIFU-phased array was developed to ablate deep tumors. In the current study, taking into account the required focal depth and maximum acoustic power output, 90 identical circular PZT-8 elements （diameter=1.4 cm and frequency=l MHz） were mounted on a spherical shell with a radius of curvature of 18 cm and a diameter of 21 cm. With the developed array, computer simulations and ex vivo experiments were carried out. The simulation results theoretically demonstrate the ability of the array to focus and steer in the specified volume （a 2 cm×2 cm×3 cm volume） at the focal depth of 15 to 18 cm. Ex vivo experiment results also verify the capability of the developed array to ablate deep target tissue by either moving single focal point or generating multiple foci simultaneously.展开更多
Deep-tissue solid cancer treatment has a poor prognosis,resulting in a very low 5-year patient survival rate.The primary challenges facing solid tumor therapies are accessibility,incomplete surgical removal of tumor t...Deep-tissue solid cancer treatment has a poor prognosis,resulting in a very low 5-year patient survival rate.The primary challenges facing solid tumor therapies are accessibility,incomplete surgical removal of tumor tissue,the resistance of the hypoxic and heterogeneous tumor microenvironment to chemotherapy and radiation,and suffering caused by off-target toxicities.Here,sonodynamic therapy(SDT)is an evolving therapeutic approach that uses low-intensity ultrasound to target deep-tissue solid tumors.The ability of ultrasound to deliver energy safely and precisely into small deep-tissue(>10 cm)volumes makes SDT more effective than conventional photodynamic therapy.While SDT is currently in phase 1/2 clinical trials for glioblastoma multiforme,its use for other solid cancer treatments,such as breast,pancreatic,liver,and prostate cancer,is still in the preclinical stage,with further investigation required to improve its therapeutic efficacy.This review,therefore,focuses on recent advances in SDT cancer treatments.We describe the interaction between ultrasound and sonosensitizer molecules and the associated energy transfer mechanism to malignant cells,which plays a central role in SDT-mediated cell death.Different sensitizers used in clinical and preclinical trials of various cancer treatments are listed,and the critical ultrasound parameters for SDT are reviewed.We also discuss approaches to improve the efficacies of these sonosensitizers,the role of the 3-dimensional spheroid in vitro investigations,ultrasound-controlled CAR-T cell and SDT-based multimodal therapy,and machine learning for sonosensitizer optimization,which could facilitate clinical translation of SDT.展开更多
As the control center of organisms, the brain remains little understood due to its complexity. Taking advantage of imaging methods, scientists have found an accessible approach to unraveling the mystery of neuroscienc...As the control center of organisms, the brain remains little understood due to its complexity. Taking advantage of imaging methods, scientists have found an accessible approach to unraveling the mystery of neuroscience. Among these methods, optical imaging techniques are widely used due to their high molecular specificity and single-molecule sensitivity. Here, we overview several optical imaging techniques in neuroscience of recent years, including brain clearing, the micro-optical sectioning tomography system, and deep tissue imaging.展开更多
One of the thorny problems currently impeding the applications of the fluorescence imaging technique is the poor spatial resolution in deep tissue.Ultrasound-switchable fluorescence(USF)imaging is a novel imaging tool...One of the thorny problems currently impeding the applications of the fluorescence imaging technique is the poor spatial resolution in deep tissue.Ultrasound-switchable fluorescence(USF)imaging is a novel imaging tool that has recently been explored to possibly surmount the above-mentioned bottleneck.Herein,αβ-cyclodextrin/indocyanine green(ICG)complex-encapsulated poly(N-isopropylacrylamide)(PNIPAM)nanogel was synthesized and studied for ex vivo/in vivo deep tissue/high-resolution near infrared USF(NIR-USF)imaging.To be specific,our results revealed that the average diameter of the as-prepared nanogels was significantly decreased to-32 nm from-335 nm compared to the reported ICG-PNIPAM nanoparticles.Additionally,the excitation/emission characteristics of the ICG itself in present nanogels were almost completely retained,and the resultant nanogel exhibited high physiological stability and positive biocompatibility.In particular,the signal-to-noise ratio of the USF image for the PNIPAM/P-cyclodextrin/ICG nanogel(33.01±2.42 dB)was prominently higher than that of the ICG-PNIPAM nanoparticles(18.73±0.33 dB)in 1.5-cm-thick chicken breast tissues.The NIR-USF imaging in 3.5-cm-thick chicken breast tissues was achieved using this new probe.The e x v iv o NIR-USF imaging of the mouse liver was also successfully obtained.Animal experiments showed that the present nanogels were able to be effectively accumulated into U87 tumor-bearing mice via enhanced permeability and retention effects,and the high-resolution NIR-USF imaging of in v ivo tumor was efficiently acquired.The metabolism and in vivo biodistribution of the nanogels were evaluated.Overall,the results suggest that the current nanogel is a highly promising NIR-USF probe for deep tissue and high-resolution USF imaging.展开更多
Three-dimensional(3D)imaging is essential for understanding intricate biological and biomedical systems,yet live cell and tissue imaging applications still face challenges due to constrained imaging speed and strong s...Three-dimensional(3D)imaging is essential for understanding intricate biological and biomedical systems,yet live cell and tissue imaging applications still face challenges due to constrained imaging speed and strong scattering in turbid media.Here,we present a unique phase-modulated stimulated Raman scattering tomography(PM-SRST)technique to achieve rapid label-free 3D chemical imaging in cells and tissue.To accomplish PM-SRST,we utilize a spatial light modulator to electronically manipulate the focused Stokes beam along the needle Bessel pump beam for SRS tomography without the need for mechanical z scanning.We demonstrate the rapid 3D imaging capability of PM-SRST by real-time monitoring of 3D Brownian motion of polystyrene beads in water with 8.5 Hz volume rate,as well as the instant biochemical responses to acetic acid stimulants in MCF-7 cells.Further,combining the Bessel pump beam with a longer wavelength Stokes beam(NIR-II window)provides a superior scattering resilient ability in PM-SRST,enabling rapid tomography in deeper tissue areas.The PM-SRST technique providestwofold enhancement in imaging depth in highly scattering media(e.g.,polymer beads phantom and biotissue like porcine skin and brain tissue)compared with conventional point-scan SRS.We also demonstrate the rapid 3D imaging ability of PM-SRST by observing the dynamic diffusion and uptake processes of deuterium oxide molecules into plant roots.The rapid PM-SRST developed can be used to facilitate label-free 3D chemical imaging of metabolic activities and functional dynamic processes of drug delivery and therapeutics in live cells and tissue.展开更多
Fluorescent probes emitting in the near-infrared zone Ⅱ(NIR-Ⅱ) spectral region(1000–1700 nm) have garnered significant attention due to their unique advantages in bioimaging and diagnostics, including deep tissue p...Fluorescent probes emitting in the near-infrared zone Ⅱ(NIR-Ⅱ) spectral region(1000–1700 nm) have garnered significant attention due to their unique advantages in bioimaging and diagnostics, including deep tissue penetration,superior spatial resolution, and minimal interference from autofluorescence or scattering in biological tissues.展开更多
基金supported by the National Natural Science Foundation of China(No.81701838)the China Postdoctoral Science Foundation(2018M632628)
文摘Background:LL-37 peptide is a member of the human cathelicidin family,and has been shown to promote the healing of pressure ulcers.However,the low stability of this peptide within the wound environment limits its clinical use.Chitosan(CS)hydrogel is commonly used as a base material for wound dressing material.Methods:CS hydrogel(2.5%w/v)was encapsulated with LL-37.Cytotoxicity of the product was examined in cultured NIH3 T3 fibroblasts.Effects on immune response was examined by measuring tumor necrosis factor-α(TNF-α)release from RAW 264.7 macrophages upon exposure to lipopolysaccharides.Antibacterial activity was assessed using Staphylococcus aureus.Potential effect on pressure ulcers was examined using a mouse model.Briefly,adult male C57 BL/6 mice were subjected to skin pressure using magnets under a 12/12 h schedule for 21 days.Mice were randomized to receive naked LL-37(20μg),chitosan gel containing 20μg LL-37(LL-37/CS hydrogel)or hydrogel alone under the ulcer bed(n=6).A group of mice receiving no intervention was also included as a control.Results:LL-37/CS hydrogel did not affect NIH3 T3 cell viability.At a concentration of 1–5μg/ml,LL-37/CS inhibited TNF-αrelease from macrophage.At 5μg/ml,LL-37/CS inhibited the growth of Staphylococcus aureus.The area of the pressure ulcers was significantly lower in mice receiving LL-37/CS hydrogel in comparison to all other 3 groups on days 11(84.24%±0.25%),13(56.22%±3.91%)and 15(48.12%±0.28%).Histological examination on days 15 and 21 showed increased epithelial thickness and density of newly-formed capillary with naked LL-37 and more so with LL-37/CS.The expression of key macromolecules in the process of angiogenesis(i.e.,hypoxia inducible factor-1α(HIF-1α)and vascular endothelial growth factor-A(VEGF-A))in wound tissue was increased at both the mRNA and protein levels.Conclusion:Chitosan hydrogel encapsulated with LL-37 is biocompatible and could promote the healing of pressure ulcers.
基金supported by National Natural Science Foundation of China(Nos.31571110 and 81771877)Natural Science Foundation of Zhejiang Province of China(LZ17F050001)the Fundamental Research Funds for the Central Universities.
文摘Two-photon microscopy normally suffers from the scattering of the tissue in biological imaging.Multidither coberent optical adaptive technique(COAT)can correct the scattered wavefront in parallel.However,the determination of the corrective phases may not be completely accurate using conventional method,which undermines the performance of this technique.In this paper,we theoretically demonstrate a method that can obtain more accurate corrective phases by determining the phase values from the square root of the fuorescence signal.A numnerical simulation model is established to study the performance of adaptive optics in two-photon micros-copy by combining scalar diffraction theory with vector diffraction theory.The results show that the distortion of the wavefront can be corrected more thoroughly with our method in two-photon imaging.In our simulation,with the scattering from a 450-mn-thick mouse brain tissue,excitation focal spots with higher peak-to background ratio(PBR)and images with higher contrast can be obtained.Hence,further enhancement of the multidither COAT correction performance in two-photon imaging can be expected.
基金supported by the Ministry of Education-Singapore(Grant Nos.MOE2019-T2-2-094 and MOE Tier I R-397-000-327-114)Shenzhen Science and Technology Program(Grant No.GJHZ20210705141805015).
文摘Structured illumination microscopy(SIM)is an established optical superresolution imaging technique.However,conventional SIM based on wide-field image acquisition is generally limited to visualizing thin cellular samples.We propose combining one-dimensional image rescan and structured illumination in the orthogonal direction to achieve superresolution without the need to rotate the illumination pattern.The image acquisition speed is consequently improved threefold,which is also beneficial for minimizing photobleaching and phototoxicity.Optical sectioning in thick biological tissue is enhanced by including a confocal slit in the system to significantly suppress the out-of-focus background and the associated noise.With all the technical improvements,our method captures threedimensional superresolved image stacks of neuronal structures in mouse brain tissue samples for a depth range of more than 200μm.
基金This work was supported by NIH R01-CA75124,R01-EB002109Susan G.Komen for the Cure Postdoctoral Fellowship provided to University of Pennsylvania,and P41-RR01192,U54-CA105480,U54CA136400,P30-CA62203 provided to University of California,Irvine.
文摘Treatment-induced apoptosis of cancer cells is one goal of cancer therapy.Interestingly,more heat is generated by mitochondria during apoptosis,especially the uncoupled apoptotic state,^(1,2) compared to the resting state.In this case study,we explore these thermal effects by longitudinally measuring temperature variations in a breast lesion of a pathological complete responder during neoadjuvant chemotherapy(NAC).Diffuse Optical Spectroscopic Imaging(DOSI)was employed to derive absolute deep tissue temperature using subtle spectral features of the water peak at 975 nm.^(3)A significant temperature increase was observed in time windows during the anthracycline and cyclophosphamide(AC)regimen but not in the paclitaxel and bevacizumab regimen.Hemoglobin concentration changes generally did not follow temperature,suggesting the measured temperature increases were likely due to mitochondrial uncoupling rather than a direct vascular effect.A simultaneous increase of tissue oxygen saturation with temperature was observed,suggesting that oxidative stress also contributes to apoptosis.Although preliminary,this study indicates longitudinal DOSI tissue temperature monitoring provides information that can improve our understanding of the mechanisms of tissue response during NAC.
基金Funding was provided by National Institutes of Health P50 GM076516by the National Center for Research Resources(5P41RR003155-27)the National Instit ute of General Medical Sciences(8 P41GM103540-27).
文摘We have developed a two-photon fluorescence microscope capable of imaging up to 4mm inturbid media with micron resolution.The key feature of this instrument is the innovative de-tector,capable of collecting emission photons from a wider surface area of the sample thandetectors in traditional two-photon microscopes.This detection scheme is extremely efficient inthe collection of emitted photons scattered by turbid media which allows eight fold increase in theimaging depth when compared with conventional two-photon microscopes.Furthermore,thissystem also has in-depth fluorescence lifetime imaging microscopy(FLiM)imaging capabilitywhich increases image contrast.The detection scheme captures emission light in a transmissionconfiguration,making it extremely efficient for the detection of second harmonic generation(SHG)signals,which is generally forward propagating.Here we present imaging experiments oftissue phantoms and in vivo and ea vivo biological tissue performed with this microscope.
基金the Shanghai Pujiang Program(No.19PJ1406400)the Interdisciplinary Program of Shanghai Jiao Tong University(Nos.YG2019ZDB02 and YG2021QN142)。
文摘Deep tissue pressure injuries(DTPIs)have witnessed a growing prevalence in hospitals and other health care units especially among individuals with pathological conditions that give rise to restricted mobility,impaired sensation,and reduced tissue tolerance.The etiology of DTPIs has been a subject of controversy,to which several explanatory models have been proposed,including direct mechanical insult,ischemia-reperfusion,lymphatic occlusion,and inflammatory cytokines.In line with these pathophysiological scenarios,ultrasound,subepidermal moisture detection,and biomarker technologies have been proposed as potential early detection methods of DTPIs.This paper provides a systematic review involving these three methods.The conclusion is that combining and implementing these methods at different time periods during DTPIs development and progression respectively is likely to be the most universal,effective and promising way for DTPIs diagnosis.
文摘Objective:analyze and discuss the clinical application of thermal therapy for deep tissue tumor in medical oncology. Methods: 54 patients admitted to the Department of Oncology of our hospital during September 2017 to June 2018 were selected as the research subjects. Combined with their admission order, they were divided into two groups. 27 patients with double number were divided into the control group, who only received radiotherapy. 27 patients with single number were divided in the study group and received thermal therapy for deep tissue tumor, and the clinical application effect of different treatment regimens in the two groups was compared. Results: the effective rate of the study group was relatively higher than that of the control group (P<0.05). Conclusion: patients have thermal therapy for deep tissue tumor in medical oncology has higher clinical efficacy and better disease control effect, with relatively high safety, feasibility and worth promoting vigorously.
基金supported by the National Natural Science Foundation of China(Nos.12474418,U22A20398,and 22135008).
文摘Lanthanide(Ln^(3+))-doped luminescent nanocrystals(NCs)with excitation and emission in the second near-infrared biological window(NIRII,1000-1700 nm)have attracted considerable attention in the fields of deep-tissue bioimaging and non-invasive biodetection,owing to their superior advantages including good photochemical stability,sharp emission peaks,large penetration depth,and high signal-to-noise ratio[1].Conventionally,Yb3t-and Nd3t-sensitized NCs have been utilized as NIR-II luminescent nanoprobes for in vivo bioimaging upon excitation with 980 and 808 nm diode laser,respectively[2].
基金supported by the National Natural Science Foundation of China(Grant No.:81703466)the Outstanding Talents Research Start-up Fund of Xuzhou Medical University,China(Grant No.:RC20552107)Xuzhou Science and Technology Bureau,China(Grant No.:KC21292).
文摘Fluorescence imaging is a noninvasive and dynamic real-time imaging technique;however,it exhibits poor spatial resolution in centimeter-deep tissues because biological tissues are highly scattering media for optical radiation.The recently developed ultrasound-controlled fluorescence(UCF)imaging is a novel imaging technique that can overcome this bottleneck.Previous studies suggest that the effective contrast agent and sensitive imaging system are the two pivotal factors for generating high-resolution UCF images ex vivo and/or in vivo.Here,this review highlights the recent advances(2015e2020)in the design and synthesis of contrast agents and the improvement of imaging systems to realize high-resolution UCF imaging of deep tissues.The imaging performances of various UCF systems,including the signal-to-noise ratio,imaging resolution,and imaging depth,are specifically discussed.In addition,the challenges and prospects are highlighted.With continuously increasing research interest in this field and emerging multidisciplinary applications,UCF imaging with higher spatial resolution and larger imaging depth may be developed shortly,which is expected to have a far-reaching impact on disease surveillance and/or therapy.
基金supported by the Academic Research Fund(AcRF)from the Ministry of Education(MOE)(Tier 2(A-8000117-01-00)Tier 1(R397-000-334-114,R397-000-371-114,and R397-000-378-114)2024 Tsinghua-NUS Joint Research Initiative Fund,and the National Medical Research Council(NMRC)(A-0009502-01-00,and A-8001143-00-00),Singapore.
文摘We report a novel stimulated Raman scattering(SRS)microscopy technique featuring phase-controlled light focusing and aberration corrections for rapid,deep tissue 3D chemical imaging with subcellular resolution.To accomplish phasecontrolled SRS(PC-SRS),we utilize a single spatial light modulator to electronically tune the axial positioning of both the shortened-length Bessel pump and the focused Gaussian Stokes beams,enabling z-scanning-free optical sectioning in the sample.By incorporating Zernike polynomials into the phase patterns,we simultaneously correct the system aberrations at two separate wavelengths(~240 nm difference),achieving a~3-fold enhancement in signal-to-noise ratio over the uncorrected imaging system.PC-SRS provides>2-fold improvement in imaging depth in various samples(e.g.,polystyrene bead phantoms,porcine brain tissue)as well as achieves SRS 3D imaging speed of~13 Hz per volume for real-time monitoring of Brownian motion of polymer beads in water,superior to conventional point-scanning SRS 3D imaging.We further utilize PC-SRS to observe the metabolic activities of the entire tumor liver in living zebrafish in cellsilent region,unraveling the upregulated metabolism in liver tumor compared to normal liver.This work shows that PCSRS provides unprecedented insights into morpho-chemistry,metabolic and dynamic functioning of live cells and tissue in real-time at the subcellular level.
基金Project supported by Wroclaw Research Centre EIT+within the project"The Application of Nanotechnology in Advanced Materials"-NanoMat(POIG.01.01.02-02-002/08)financed by the European Regional Development Fund(Operational Programme Innovative Economy,1.1.2)
文摘Optical imaging plays an important role in biomedical research being extremely useful for early detection, screening and image-guided therapy. Lanthanide-doped up-converting nanoparticles were ideally suited for bioimaging because they could be ex- cited in near infrared （NIR） and emit in NIR or visible （VIS）. Here, we compared lanthanide doped up-converting NaYF4 and organic fluorophores for application in deep-tissue imaging. For that purpose - tissue phantoms mimicking the natural properties of light scat- tering by living tissues were prepared. The studies allowed to quantitatively compare optical resolution of different fluorescent com- pounds, revealing that the NIR photoexcitation was favorable over conventional UV photoexcitation.
基金Authors acknowledge funding from the National Natural Science Foundation of China(grant Nos.51773043,81772363 and 21975045)the National Key R&D Program of China(grant Nos.2020YFC1107102 and 2016YFC1100300).
文摘It is very challenging to visualize implantable medical devices made of biodegradable polymers in deep tissues.Herein,we designed a novel macromolecular contrast agent with ultrahigh radiopacity(iodinate content>50%)via polymerizing an iodinated trimethylene carbonate monomer into the two ends of poly(ethylene glycol)(PEG).A set of thermosensitive and biodegradable polyester-PEG-polyester triblock copolymers with varied polyester compositions synthesized by us,which were soluble in water at room temperature and could spontaneously form hydrogels at body temperature,were selected as the demonstration materials.The addition of macromolecular contrast agent did not obviously compromise the injectability and thermogelation properties of polymeric hydrogels,but conferred them with excellent X-ray opacity,enabling visualization of the hydrogels at clinically relevant depths through X-ray fluoroscopy or Micro-CT.In a mouse model,the 3D morphology of the radiopaque hydrogels after injection into different target sites was visible using Micro-CT imaging,and their injection volume could be accurately obtained.Furthermore,the subcutaneous degradation process of a radiopaque hydrogel could be non-invasively monitored in a real-time and quantitative manner.In particular,the corrected degradation curve based on Micro-CT imaging well matched with the degradation profile of virgin polymer hydrogel determined by the gravimetric method.These findings indicate that the macromolecular contrast agent has good universality for the construction of various radiopaque polymer hydrogels,and can nondestructively trace and quantify their degradation in vivo.Meanwhile,the present methodology developed by us affords a platform technology for deep tissue imaging of polymeric materials.
基金This work was financially supported by the China Postdoctoral Science Foundation(No.2019M661026)the National Key Research and Development Program of China(No.2021YFF1200700)+3 种基金the National Natural Science Foundation of China(Nos.91859101,81971744,U1932107,814717866,and 11804248)the Natural Science Foundation of Tianjin(Nos.20JCQNJC01270 and 21JCBJC00460)the Public Health Science and Technology Major Project of Tianjin(No.21ZXGWSY00070)the Independent Innovation Foundation Tianjin University(No.2021XT-0018).
文摘Fluorescence imaging has become an essential tool in biomedical research.However,non-invasive deep-tissue threedimensional optical in vivo imaging with the high spatiotemporal resolution is challenging due to the interaction between photons and tissues.Beam shaping has been used to tailor microscopy techniques to enhance microscope performance.The nearinfrared window(NIR)between 700 and 1,700 nm,generally emphasized as the NIR-II(1,000–1,700 nm)window,has been developed into a promising bio-optical solution chosen as the lower interaction effect in this spectrum,showing potential in basic biological research and clinical application.In this review,we summarize the existing methods to increase penetration depth and extensively describe biological microscopy techniques,NIR-II spectral windows,and fluorophores.Strategies to improve bioimaging performance and NIR-II imaging applications are introduced.Based on the current research achievements,we elucidate the main challenges and provide some recommendations and prospects for deep tissue penetration fluorescence for future biomedical applications.
基金supported by the National Natural Science Foundation of China(No.61178089/81201124)in part by the Natural Science Foundation of Fujian Province(No.2011Y0019)
文摘Measurement of light distribution in biological tissue contributes to selecting strategy and optimizing dose for biomedical application. In this letter, a photoacoustic method combined with Monte Carlo simulation was used to estimate the three-dimensional light distribution in biological tissue. The light distribution was produced by a cylindrical diffuser which interposed into tissues. The light profiles obtained by the method were compared to those detected by photo diodes. The experimental results demonstrate the feasibility of this method. The approach can play a significant role for photo-dosimetry in biomedical phototherapy.
基金supported by the National Natural Science Foundation of China (No. 30800246)Shanghai Key Technologies R&D Programof China (No. 09441900500)
文摘Under some circumstances surgical resection is feasible in a low percentage for the treatment of deep tumors. Nevertheless, high-intensity focused ultrasound （HIFU） is beginning to offer a potential noninvasive alternative to conventional therapies for the treatment of deep tumors. In our previous study, a large scale spherical HIFU-phased array was developed to ablate deep tumors. In the current study, taking into account the required focal depth and maximum acoustic power output, 90 identical circular PZT-8 elements （diameter=1.4 cm and frequency=l MHz） were mounted on a spherical shell with a radius of curvature of 18 cm and a diameter of 21 cm. With the developed array, computer simulations and ex vivo experiments were carried out. The simulation results theoretically demonstrate the ability of the array to focus and steer in the specified volume （a 2 cm×2 cm×3 cm volume） at the focal depth of 15 to 18 cm. Ex vivo experiment results also verify the capability of the developed array to ablate deep target tissue by either moving single focal point or generating multiple foci simultaneously.
文摘Deep-tissue solid cancer treatment has a poor prognosis,resulting in a very low 5-year patient survival rate.The primary challenges facing solid tumor therapies are accessibility,incomplete surgical removal of tumor tissue,the resistance of the hypoxic and heterogeneous tumor microenvironment to chemotherapy and radiation,and suffering caused by off-target toxicities.Here,sonodynamic therapy(SDT)is an evolving therapeutic approach that uses low-intensity ultrasound to target deep-tissue solid tumors.The ability of ultrasound to deliver energy safely and precisely into small deep-tissue(>10 cm)volumes makes SDT more effective than conventional photodynamic therapy.While SDT is currently in phase 1/2 clinical trials for glioblastoma multiforme,its use for other solid cancer treatments,such as breast,pancreatic,liver,and prostate cancer,is still in the preclinical stage,with further investigation required to improve its therapeutic efficacy.This review,therefore,focuses on recent advances in SDT cancer treatments.We describe the interaction between ultrasound and sonosensitizer molecules and the associated energy transfer mechanism to malignant cells,which plays a central role in SDT-mediated cell death.Different sensitizers used in clinical and preclinical trials of various cancer treatments are listed,and the critical ultrasound parameters for SDT are reviewed.We also discuss approaches to improve the efficacies of these sonosensitizers,the role of the 3-dimensional spheroid in vitro investigations,ultrasound-controlled CAR-T cell and SDT-based multimodal therapy,and machine learning for sonosensitizer optimization,which could facilitate clinical translation of SDT.
基金supported by the National Basic Research Development Program(973 Program)of China(2015CB352005)the National Natural Science Foundation of China(6142780065,81527901,and 31571110)+1 种基金Natural Science Foundation of Zhejiang Province of China(Y16F050002)Fundamental Research Funds for the Central Universities of China
文摘As the control center of organisms, the brain remains little understood due to its complexity. Taking advantage of imaging methods, scientists have found an accessible approach to unraveling the mystery of neuroscience. Among these methods, optical imaging techniques are widely used due to their high molecular specificity and single-molecule sensitivity. Here, we overview several optical imaging techniques in neuroscience of recent years, including brain clearing, the micro-optical sectioning tomography system, and deep tissue imaging.
基金This work was supported in part by funding from the CPRIT RP170564(Baohong Yuan)and the NSF CBET-1253199(Baohong Yuan).
文摘One of the thorny problems currently impeding the applications of the fluorescence imaging technique is the poor spatial resolution in deep tissue.Ultrasound-switchable fluorescence(USF)imaging is a novel imaging tool that has recently been explored to possibly surmount the above-mentioned bottleneck.Herein,αβ-cyclodextrin/indocyanine green(ICG)complex-encapsulated poly(N-isopropylacrylamide)(PNIPAM)nanogel was synthesized and studied for ex vivo/in vivo deep tissue/high-resolution near infrared USF(NIR-USF)imaging.To be specific,our results revealed that the average diameter of the as-prepared nanogels was significantly decreased to-32 nm from-335 nm compared to the reported ICG-PNIPAM nanoparticles.Additionally,the excitation/emission characteristics of the ICG itself in present nanogels were almost completely retained,and the resultant nanogel exhibited high physiological stability and positive biocompatibility.In particular,the signal-to-noise ratio of the USF image for the PNIPAM/P-cyclodextrin/ICG nanogel(33.01±2.42 dB)was prominently higher than that of the ICG-PNIPAM nanoparticles(18.73±0.33 dB)in 1.5-cm-thick chicken breast tissues.The NIR-USF imaging in 3.5-cm-thick chicken breast tissues was achieved using this new probe.The e x v iv o NIR-USF imaging of the mouse liver was also successfully obtained.Animal experiments showed that the present nanogels were able to be effectively accumulated into U87 tumor-bearing mice via enhanced permeability and retention effects,and the high-resolution NIR-USF imaging of in v ivo tumor was efficiently acquired.The metabolism and in vivo biodistribution of the nanogels were evaluated.Overall,the results suggest that the current nanogel is a highly promising NIR-USF probe for deep tissue and high-resolution USF imaging.
基金supported by the Academic Research Fund(AcRF)-Tier 2(A-8000117-01-00)and Tier 1(R397-000334-114,R397-000-371-114,and R397-000-378-114)from the Ministry of Education(MOE)the Merlion Fund(WBS R-397-000-356-133)the National Medical Research Council(NMRC)(A-0009502-01-00 and A-8001143-00-00),Singapore
文摘Three-dimensional(3D)imaging is essential for understanding intricate biological and biomedical systems,yet live cell and tissue imaging applications still face challenges due to constrained imaging speed and strong scattering in turbid media.Here,we present a unique phase-modulated stimulated Raman scattering tomography(PM-SRST)technique to achieve rapid label-free 3D chemical imaging in cells and tissue.To accomplish PM-SRST,we utilize a spatial light modulator to electronically manipulate the focused Stokes beam along the needle Bessel pump beam for SRS tomography without the need for mechanical z scanning.We demonstrate the rapid 3D imaging capability of PM-SRST by real-time monitoring of 3D Brownian motion of polystyrene beads in water with 8.5 Hz volume rate,as well as the instant biochemical responses to acetic acid stimulants in MCF-7 cells.Further,combining the Bessel pump beam with a longer wavelength Stokes beam(NIR-II window)provides a superior scattering resilient ability in PM-SRST,enabling rapid tomography in deeper tissue areas.The PM-SRST technique providestwofold enhancement in imaging depth in highly scattering media(e.g.,polymer beads phantom and biotissue like porcine skin and brain tissue)compared with conventional point-scan SRS.We also demonstrate the rapid 3D imaging ability of PM-SRST by observing the dynamic diffusion and uptake processes of deuterium oxide molecules into plant roots.The rapid PM-SRST developed can be used to facilitate label-free 3D chemical imaging of metabolic activities and functional dynamic processes of drug delivery and therapeutics in live cells and tissue.
基金supported by the National Key Research and Development Program of China(2023YFB3810001)the National Natural Science Foundation of China(52333007,52273197,52250410355)+3 种基金the Shenzhen Key Laboratory of Functional Aggregate Materials(ZDSYS20211021111400001)the Science Technology Innovation Commission of Shenzhen Municipality(GJHZ20210705141810031,KQTD20210811090142053,JCYJ20220818103007014,LGKCYLWS2023017)the Innovation and Technology Commission(ITC-CNERC14SC01)the Science and Technology Program of Guangzhou,China(2023A04J0069).
文摘Fluorescent probes emitting in the near-infrared zone Ⅱ(NIR-Ⅱ) spectral region(1000–1700 nm) have garnered significant attention due to their unique advantages in bioimaging and diagnostics, including deep tissue penetration,superior spatial resolution, and minimal interference from autofluorescence or scattering in biological tissues.
