Fig. 1. Pdots for bio-optical applications

Fig. 2. Jablonski diagram

Fig. 3. Modification and functionalization of Pdots. (a) Pdots co-precipitated with the amphiphilic polymer PSMA by click chemistry for bioorthogonal labeling, reproduced from Ref.[67] with permission; (b) preparation of cross-linked PFBT-NH-PIMA Pdots coupled chain protein, reproduced from Ref.[81] with permission; (c) poly(ethylene glycol) and carboxyl functionalization of Pdots for cell-targeted, reproduced from Ref.[82] with permission

Fig. 4. Application of Pdots-based NADH biosensing in the detection of phenylalanine, reproduced from Ref.[88] with permission. (a) Schematic diagram of the NADH-sensitive Pdots-based phenylalanine biosensor; (b) fluorescence emission changes from red (Pdots) to blue (NADH) with increasing phenylalanine concentration, and metabolite concentration is measured ratiometrically-based on the ratio of blue-to-red channel emission intensities, with a digital camera or plate reader-in solution- or paper-based assay formats; (c) fluorescence emission of the Pdots biosensor at 0-2400 μmol/L phenylalanine; (d) calibration for endogenous NADH; (e) calibration curve for phenylalanine detection test strips

Fig. 5. Pdots-based biosensor for wireless glucose monitoring. (a) Changes in fluorescence from PD4Gx before and after glucose injection in mice, reproduced from Ref.[90] with permission; (b) calibration curve of PD4Gx red/blue channel ratio versus glucose concentration, reproduced from Ref.[90] with permission; (c) schematic of the Pdots-GOx/CAT glucose biosensor, reproduced from Ref.[91] with permission; (d) emission ratio curves of Pdots-GOx/CAT biosensor in the presence of different concentrations of exogenous hydrogen peroxide after the addition of glucose, reproduced from Ref.[91] with permission; (e) linear correlation between the fluorescence emission ratio of the Pdots-GOx/CAT biosensor and glucose concentration over a range of physiological concentrations, reproduced from Ref.[91] with permission; (f) linear correlation between the normalized fluorescence intensity and glucose concentration in mice 28 days after subcutaneous implantation of the hydrogel-Pdots biosensor, reproduced from Ref.[93] with permission

Fig. 6. Pdots-based DNA and microRNA biosensing. (a) Schematic of PF-DNAP Pdots for DNA detection, reproduced from Ref.[96] with permission; (b) variation of photoluminescence spectra of PF-DNAP Pdots at different concentrations of ssDNAC, the inset shows fluorescence images of PF-DNAP Pdots with/without ssDNAC, reproduced from Ref.[96] with permission; (c) schematic of PFBT-COOH Pdots-based biosensor, reproduced from Ref.[98] with permission; (d) ECL response of the PFBT-COOH Pdots-based biosensor to different concentrations of miRNA-155, reproduced from Ref.[98] with permission; (e) calibration curve of ECL intensity versus logarithm of miRNA-155 concentration, reproduced from Ref.[98] with permission

Fig. 7. Pdots-based ICTS for tumor marker detection.(a) Structure of ICTS for CEA/AFP/PSA multiplex detection, reproduced from Ref.[101] with permission; (b) images of detection at different mass concentrations (0/0/5, 0/5/0, 5/0/0, 5/5/5 ng/mL) of tumor markers, reproduced from Ref.[101] with permission; (c) schematic of FRET-based traffic signal light ICTS, reproduced from Ref.[102] with permission; (d) ICTS fluorescence images under 410 nm UV excitation with 600 nm high-pass filter, reproduced from Ref.[102] with permission; (e) calibration curve of Au650@Pdot ICTS at 3-10 ng/mL PSA, reproduced from Ref.[103] with permission; (f) images of Au@Pdot ICTS containing different concentrations of CYFRA21-1 and CEA obtained under ambient light and UV light, reproduced from Ref.[104] with permission

Fig. 8. Pdots-based biosensor for enzyme activity. (a) Schematic of the PFO and MOF-based MMP-2 biosensor, reproduced from Ref.[105] with permission; (b) calibration curve of biosensor fluorescence intensity versus MMP-2 mass concentration, reproduced from Ref.[105] with permission; (c) schematic of Tyr-OMe-functionalized TR biosensor, reproduced from Ref.[106] with permission; (d) two-photon fluorescence spectra of the Pdots@Tyr-OMe biosensor at different TR concentrations, reproduced from Ref.[106] with permission; (e) correlation of fluorescence intensity ratio (I₅₈₆/I₄₄₁) with TR concentration, reproduced from Ref.[106] with permission; (f)(g) fluorescence response to GO-Pep-Pdots at different concentrations of MMP-9 and the fluorescence recovery after fluorescence quenching, reproduced from Ref.[37] with permission

Fig. 9. Pdots-based fluorescence imaging. (a) Long-term in vivo fluorescence and bright-field imaging of mice injected with HeLa cells cultured with NIR Pdots, and in vitro fluorescence imaging of tumors from mice 23 days post-injection, reproduced from Ref.[120] with permission; (b) CLSM images of the cells treated with ultra-small cRGD-CPN6, where pre-treated HeLa and NIH-3T3 cells have green emission and MDA-MB-231 cells have red emission, reproduced from Ref.[121] with permission; (c) real-time NIR-Ⅱ fluorescence imaging of tumors in nude mouse via tail vein injection of P1-Pdots, reproduced from Ref.[122] with permission; (d) NIR-Ⅱ fluorescence images of mice in prone and supine positions via tail vein injection of m-PBTQ4F, right images shows the cross-sectional fluorescence intensity distribution measured along the white line, reproduced from Ref.[118] with permission

Fig. 10. Pdots-based NIR-Ⅱ PAI. (a) In vivo US/PA bimodal imaging in mouse tumors uninjected (top) and injected (bottom) TSNP, reproduced from Ref.[138] with permission; (b) US/PA images of brain tumors before and after P1 Pdots injection, grey US images showing skin and skull margins and green signal in PA images showing the distribution of P1 Pdots, reproduced from Ref.[139] with permission; (c) degradation and metabolic processes of SPN-PT Pdots in phagocytes, reproduced from Ref. [141] with permission; (d) superficial tumor and cerebrovascular PA images of mice injected with SPN-PT Pdots at designed time points under 1064 nm irradiation, reproduced from Ref.[141] with permission

Fig. 11. Pdots-based multimodal imaging. (a) PA signal intensity and (b) fluorescence signal intensity versus time after drug injection (rSPN2 and SPN2 Pdots), reproduced from Ref.[146] with permission; (c) IVIS-treated images of mice after injection of Gd-SPNs; (d) linear correlation between relaxation rate values (R1) and gadolinium concentration of Gd-SPNs, reproduced from Ref.[147] with permission; (e) dark field and fluorescence images of Au-NP-Pdots in mammalian cells, reproduced from Ref.[148] with permission; (f) PA images of brain tumor mouse’s brain 12 h after injection of cRGD-CM-CPIO nanocomposites, reproduced from Ref.[149] with permission

Fig. 12. Pdots-based PTT. (a) Photothermal heating and cooling curves of SPN_I-Ⅱ Pdots solution at different laser power densities, the inset shows the infrared thermal images at the corresponding maximum temperature, reproduced from Ref.[167] with permission; (b) variation of mean tumor temperature with laser irradiation time after injection of SPN_I-Ⅱ Pdots, reproduced from Ref.[167] with permission; (c) schematic of F8-PEG Pdots biodegradation, reproduced from Ref. [168] with permission; (d) infrared thermal images of nude mice after different treatments, reproduced from Ref.[168] with permission; (e) tumor temperature change curves under different groups of laser irradiation, reproduced from Ref.[168] with permission; (f) schematic of in vivo PTT and PAI of brain tumors with P1RGD Pdots, reproduced from Ref.[174] with permission

Fig. 13. Pdots-based PDT. (a) Oxygen sensing and PDT mechanism of Ir(Ⅲ)-doped Pdots, reproduced from Ref.[180] with permission; (b) efficient FRET between Pdots and m-THPC increases single-linear state oxygen production, reproduced from Ref.[181] with permission; (c) PDT mechanism of Ce6 photo-crosslinked Pdots, reproduced from Ref. [182] with permission; (d) changes in relative tumor volume (top) and body weight (bottom) of nude mice after treatment, reproduced from Ref.[182] with permission

Fig. 14. Pdots-based photoimmunotherapy and photoimmunometabolic therapy. (a) Preparation of NIR-Ⅱ photoimmunotherapeutic agent SPN_ⅡR, reproduced from Ref.[186] with permission; (b) preparation of NIR-Ⅱ photoinduced immunotherapeutic agent APNA, reproduced from Ref.[187] with permission; (c) mechanism of NIR photoactivated photoimmunometabolic therapeutic agent SPNK, reproduced from Ref.[193] with permission