The emergence of nonconventional luminescent materials(NLMs)has attracted significant attention due to their sustainable synthesis and tunable optical properties.Yet,establishing a clear structure-emission relationshi...The emergence of nonconventional luminescent materials(NLMs)has attracted significant attention due to their sustainable synthesis and tunable optical properties.Yet,establishing a clear structure-emission relationship remains a challenge.In this work,we report a previously unknown class of NLMs:cross-linked protein crystals that exhibit intense photoluminescence(PL)in the visible range(425-680 nm).We systematically investigated seven natural protein crystals(concanavalin,catalase,lysozyme,hemoglobin,α-chymotrypsin,pepsin,and β-lactoglobulin)cross-linked with glutaraldehyde and demonstrated that cross-linking induces broadband emission that is absent in natural crystals.Focusing on polymorphic lysozyme crystals(tetragonal,orthorhombic,and monoclinic),we found excitation-dependent fluorescence with lifetimes in the nanosecond range and quantum yields up to 20%(in themonoclinic phase under 450 nmexcitation).Single-and two-photon spectroscopy,as well as pressure-and solvent-modulated PL studies,confirm that the emission is due to intermolecular through-space interactions(TSI)within the crystal lattice.Compression enhances TSI and redshifts the emission,whereas the solvent(DMSO)-induced swelling reduces TSI and causes a blue shift,establishing a direct structure-emission correlation.This work establishes protein crystals as programmableNLMswith tunable emission and provides a mechanistic framework for the design of nonconventional luminogens through protein crystal engineering.展开更多
基金support from the National Key R&D Program of China(2021YFF0502900)the National Natural Science Foundation of China(62127819,T2421003,62435011,32471230,W2431056)+2 种基金the Shenzhen Key Laboratory of Photonics and Biophotonics(ZDSYS20210623092006020)the Shenzhen Science and Technology Program(JCYJ20220818100202005)and the Fundamental Research Funds for the Central Universities(23GH02021).
文摘The emergence of nonconventional luminescent materials(NLMs)has attracted significant attention due to their sustainable synthesis and tunable optical properties.Yet,establishing a clear structure-emission relationship remains a challenge.In this work,we report a previously unknown class of NLMs:cross-linked protein crystals that exhibit intense photoluminescence(PL)in the visible range(425-680 nm).We systematically investigated seven natural protein crystals(concanavalin,catalase,lysozyme,hemoglobin,α-chymotrypsin,pepsin,and β-lactoglobulin)cross-linked with glutaraldehyde and demonstrated that cross-linking induces broadband emission that is absent in natural crystals.Focusing on polymorphic lysozyme crystals(tetragonal,orthorhombic,and monoclinic),we found excitation-dependent fluorescence with lifetimes in the nanosecond range and quantum yields up to 20%(in themonoclinic phase under 450 nmexcitation).Single-and two-photon spectroscopy,as well as pressure-and solvent-modulated PL studies,confirm that the emission is due to intermolecular through-space interactions(TSI)within the crystal lattice.Compression enhances TSI and redshifts the emission,whereas the solvent(DMSO)-induced swelling reduces TSI and causes a blue shift,establishing a direct structure-emission correlation.This work establishes protein crystals as programmableNLMswith tunable emission and provides a mechanistic framework for the design of nonconventional luminogens through protein crystal engineering.
