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Photosensitizers (PSs) are light‐sensitive molecules that are highly hydrophobic, which poses a challenge to their use for targeted photodynamic therapy. Hence, considerable efforts have been made to develop carriers for the delivery of PSs. Herein, a novel design is described of highly biocompatible, fluorescent, folic acid (FA)‐functionalized carbon nanodots (CDs) as carriers for the PS zinc phthalocyanine (ZnPc) to achieve simultaneous biological imaging and targeted photodynamic therapy. FA is modified on PEG‐­passivated CDs (CD‐PEG) for targeted delivery to FA‐positive cancer cells, and ZnPc is loaded onto CD‐PEG‐FA via π–π stacking interactions. CD‐PEG‐FA/ZnPc exhibits excellent targeted delivery of the PS, leading to simultaneous imaging and significant targeted photodynamic therapy after irradiation in vitro and in vivo. The present CD‐based targeted delivery of PSs is anticipated to offer a convenient and effective platform for enhanced photodynamic therapy to treat cancers in the near future.

Carbon nanodots (CDs) were initially synthesized by dehydrating carbohydrates using a commercial household microwave (700 W). To prepare BN-CD, 960 mg of citric acid (5.0 mmol, Aldrich) and 310 mg of boric acid (5.0 mmol) were dissolved in 10 mL of water. To this transparent solution, 347 µL of EDA (5.0 mmol) was added under vigorous stirring for 2 min. The solution was placed into a microwave oven and heated for 2 min, and a yellow solid was obtained after cooling to room temperature. The solid was diluted in 5.0 mL of water. The yellow suspension was dialyzed (SpectraPore MWCO 500 -1,000) for 2 days to remove salts and unreacted chemicals. To synthesize N-CD, microwave pyrolysis was performed in the absence of boric acid. BN-CD0.5 and BN-CD2 were prepared with 2.5 mmol (0.5 equiv. of citric acid and ethylene diamine) and 10 mmol (2 equiv. of citric acid and ethylene diamine) of boric acid, with the same concentrations of other precursors as described above. Non-doped plain CD was synthesized with 5 mmol of citric acid through hydrothermal method at 180 o C for 6 hr. B-CD was synthesized with 5 mmol of boric acid and citric acid.

The development of cost-effective and environmentally friendly photocatalysts and photosensitizers has received tremendous attention because of their potential utilization in solar-light-harvesting applications. In this respect, carbon dots (CDs) prepared by bottom-up methods have been considered to be promising light-harvesting materials. Through their preparation from various molecular precursors and synthetic methods, CDs exhibit excellent optical and charge-transfer properties. Furthermore, their photophysical properties can be readily optimized and enhanced by means of doping, functionalization, and post-synthetic treatment. In this review, we summarize the recent progress in CDs synthesized using bottom-up approaches. These CDs exhibit strong light absorption and unique electron donor/acceptor capabilities for light-harvesting applications. We anticipate that this review will provide new insights into novel types of photosensitizers and photocatalysts for a wide range of applications.

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Nanofibrous scaffolds are artificial extracellular matrices which provide natural environment for tissue formation. In comparison to other forms of scaffolds, the nanofibrous scaffolds promote cell adhesion, proliferation and differentiation more efficiently due to having high surface to volume ratio. Although scaffolds for tissue engineering have been fabricated by various techniques but electrospun nanofibrous scaffolds have shown great potential in the fields of tissue engineering and regeneration. This review highlights the applications and importance of electrospun nanofibrous scaffolds in various fields of biomedical applications ranging from drug delivery to wound healing. Attempts have also been made to highlights the advantages and disadvantages of nanofirbous scaffolds fabricated for biomedical applications using technique of electrospinning. The role of various factors controlling drug distribution in electrospun nanofibrous scaffolds is also discussed to increase the therapeutic efficiency of nanofibrous scaffolds in wound healing and drug delivery applications.

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