Sustainable synthesis of lignin-derived carbon dots with visible pH response for Fe3+ detection and bioimaging

Lignin-Based Carbon Nanomaterials for Biochemical Sensing Applications

Lignin-based carbon nanomaterials offer several advantages, including biodegradability, biocompatibility, high specific surface area, ease of functionalization, low toxicity, and cost-effectiveness. These materials show promise in biochemical sensing applications, particularly in the detection of metal ions, organic compounds, and human biosignals. Various methods can be employed to synthesize carbon nanomaterials with different dimensions ranging from 0D-3D, resulting in diverse structures and physicochemical properties. This study provides an overview of the preparation techniques and characteristics of multidimensional (0-3D) lignin-based carbon nanomaterials, such as carbon dots (CDs), carbon nanotubes (CNTs), graphene, and carbon aerogels (CAs). Additionally, the sensing capabilities of these materials are compared and summarized, followed by a discussion on the potential challenges and future prospects in sensor development.

State-of-the-art of lignin-derived carbon nanodots: Preparation, properties, and applications

Lignin-derived carbon nanodots (LCNs) are nanometer-scale carbon spheres fabricated from naturally abundant lignin. Owing to rich and highly heritable graphene like π-π conjugated structure of lignin, to fabricate LCNs from it not only endows LCNs with on-demand tunable size and optical features, but also further broadens the green and chemical engineering of carbon nanodots. Recently, they have become increasingly popular in sensing, bioimaging, catalysis, anti-counterfeiting, energy storage/conversion, and others. Despite the enormous research efforts put into the ongoing development of lignin value-added utilization, few commercial LCNs are available. To have a deeper understanding of this issue, critical impacts on the preparation, properties, and applications of state-of-the-art LCNs are carefully reviewed and discussed. A concise analysis of their unique advantages, limitations for specific applications, and current challenges and outlook is conducted. We hope that this review will stimulate further advances in the functional material-oriented production of lignin.

Comprehensive Overview of Controlled Fabrication of Multifunctional Fluorescent Carbon Quantum Dots and Exploring Applications

In recent years, carbon dots (CDs) have garnered increasing attention due to their simple preparation methods, versatile performances, and wide-ranging applications. CDs can manifest various optical, physical, and chemical properties including quantum yield (QY), emission wavelength (Em), solid-state fluorescence (SSF), room-temperature phosphorescence (RTP), material-specific responsivity, pH sensitivity, anti-oxidation and oxidation, and biocompatibility. These properties can be effectively regulated through precise control of the CD preparation process, rendering them suitable for diverse applications. However, the lack of consideration given to the precise control of each feature of CDs during the preparation process poses a challenge in obtaining the requisite features for various applications. This paper is to analyze existing research and present novel concepts and ideas for creating CDs with different distinct features and applications. The synthesis methods of CDs are discussed in the first section, followed by a comprehensive overview of the important properties of CDs and the modification strategy. Subsequently, the application of CDs and their requisite properties are reviewed. Finally, the paper outlines the current challenges in controlling CDs properties and their applications, discusses potential solutions, and offers suggestions for future research.

Recent developments in lignin-based fluorescent materials

Biomass-based fluorescent materials are an alternative to plastic-based materials for their multifunctional applications. Lignin, an inexpensive and easily available raw material, demonstrates outstanding environment-responsive properties such as pH, metal ions, dyes sensing, bioimaging and so on. To date, only a little work has been reported on the synthesis of lignin-based fluorescent materials. In this review report, synthetic approaches and light-responsive applications of lignin-based fluorescent carbon dots and other materials are summarized. The results reveal that lignin-based fluorescent carbon dots are prepared by hydrothermal method, exhibit small size <10 nm, reveal significant quantum yield, biocompatibility, non-toxicity, photostability and display substantial tunable emission and can be efficiently employed for sensing, bioimaging and energy storage applications. Finally, the forthcoming challenges, investigations, and options open for the chemical and/or physical modification of lignin into fluorescent materials for future applications are well-addressed. To our knowledge, this is the first comprehensive review report on lignin-based fluorescent materials and their light-responsive applications. In addition, this review will attract remarkable consideration and thrust for the researchers and biochemical technologists working with the preparation of lignin-based fluorescent materials for broad applications.