The Emerging Next-Generation Materials for Biomedical Applications

1. Introduction

Carbon dots (CDs) have emerged as a promising class of nanomaterials with unique properties, making them highly attractive for various biomedical applications. These nanoscale carbon-based structures exhibit exceptional optical, electronic, and biocompatible properties, rendering them suitable for applications ranging from bioimaging and drug delivery to biosensing and photothermal therapy. Since the groundbreaking discovery of nanoscience and nanotechnology, it has emerged as a new frontier in the global scientific community. Nanomaterials' unique optoelectronic and physicochemical properties, as opposed to their bulk structures, have been the driving force behind this development which is reported by Mondal et al., 2014. Composite materials consisting of Carbon Dots (CDs) and polymers have garnered significant attention for applications in biochemistry, biology, and biomedicine due to their easy preparation, cost-effective processing, and biocompatibility reported by Ganguly et al., 2019. CDs can be easily synthesized from a range of natural and synthetic sources. The production of CD/polymer composites involves the straightforward mixing of polymers and CDs, with or without additional treatments (Waidi et al., 2023). While blending polymers and nanomaterials is not a new synthesis process, the ongoing research focuses on developing improved CD/polymer composite materials that demonstrate favorable biocompatibility and optoelectrical properties. Various polymer architectures, including homo- and co-polymers, hyperbranched polymers, and diverse polymeric chains, have been utilized to anchor and coat CDs, resulting in the fabrication of biocompatible CD/polymer hybrid composite materials. Recent studies indicate that several methods, such as ligand exchange between polymers and CDs, grafting polymers to CDs, grafting polymers from CDs, capping polymers onto CDs, and growing CDs within the polymer template, are commonly employed for the production of biocompatible CD/polymer composite materials (Foubert et al., 2016) (Zhou et al., 2017). The straightforward preparation and outstanding properties of CDs, along with the cross-linked polymeric attributes, have sparked interest in potential applications, such as drug delivery systems, photodynamic therapy, bioimaging, etc., within the field of biomedical sciences reported by Sharker et al., 2021. Carbon dots, characterized by small carbon nanoparticles with a size <10 nm and surface passivation, have become particularly noteworthy (Datta et al., 2023). Their composition, derived from carbon—an abundant and non-toxic element, a fundamental building block of the human body—renders them attractive for various applications. This is especially true in fields where concerns about toxicity are paramount, such as biological imaging, drug/gene delivery, solar cell fabrication, and photonic device fabrication. Unlike other nanomaterials and quantum dots, carbon dots exhibit biocompatibility, eliminating the need to worry about environmental effects, toxicity, or production costs. The unique structural and electronic properties arising from the carbon composition set carbon dots apart from other nanomaterials.

Figure 1.

(a) Schematic diagram of the synthesis of CDs from starting materials (first) and fabrication of CD/polymer composite materials (second). (b) CD/polymer composite materials are being proposed for biomedical applications (Sharker et al., 2021).