Zhiqiang Yu

Heteroatom-doped carbon dots: synthesis, characterization, properties, photoluminescence mechanism and biological applications

Heteroatom-doped carbon dots (CDs), due to their excellent photoluminescence (PL) properties, attracted widespread attention recently and demonstrated immense promise for diverse applications, particularly for biological applications. The objective of this feature article is to provide a comprehensive overview of the recent progress in the research and development of heteroatom-doped CDs and a detailed description of the influence of single or co-doping heteroatoms on their PL behavior. The most recent understanding and critical insights into the PL mechanism of heteroatom-doped CDs are also highlighted. Moreover, potential bio-related applications of heteroatom-doped CDs in biosensing, bioimaging, and theranostics are also reviewed. This state-of-the-art review will provide a platform for understanding the intricate details of heteroatom-doped CDs, a summary of the latest progress in the field, and related applications in biology and is expected to inspire further developments in this exciting class of materials.

Self-Assembling Peptide Nanofibrous Hydrogel as a Versatile Drug Delivery Platform

Molecular hydrogels have been widely explored in various biomedical applications, such as cell culture, tissue engineering and drug delivery. Peptide-based hydrogel nanoparticles represent a promising alternative to current drug delivery approaches and cell carriers for tissue engineering, due to their encapsulation stability, water solubility and biocompatibility. This review focuses on recent advances in the use of self-assembling peptide nanogels for applications in drug delivery. We firstly introduce a self-assembly mechanism for small molecules used in the peptide hydrogel, and then describe recent methods for controlling the assembly of molecular hydrogelations. A particular emphasis is placed on recent advances in the use of different types of peptide hydrogels as drug delivery carriers. Lastly, the current challenges and future perspectives for self-assembling peptide hydrogels in drug delivery applications are discussed.

Targeted Delivery of Bleomycin: A Comprehensive Anticancer Review

Despite being one of the most effective broad-spectrum chemotherapeutic agents in the treatment of cancers, the clinical applications of bleomycins (BLMs) have been limited due to their poor drug delivery abilities, and the side effect of causing lung fibrosis. With the increased therapeutics and the reduction of side effects, research and development of targeted drug delivery systems (TDDS) with BLMs have become essential for the expansive clinical usage of BLM-based therapeutics. This review summarizes the recent developments of various TDDS for BLMs, including techniques such as photochemical internalization, ultrasound, and micelle, liposome, and nanoparticle formation. The advantages and disadvantages for each delivery approach are outlined, along with the specific challenges associated with each delivery system.

iRGD-decorated red shift emissive carbon nanodots for tumor targeting fluorescence imaging

Carbon nanodots (CDs) have been exhibiting increasing applications owing to their luminescence properties and biocompatibility as imaging probes in diagnosis. However, poor tumor targeting and penetration of CDs is still the biggest challenge limiting their tumor imaging efficacy. To improve the tumor targeting and penetration efficiency of CDs, we developed an active tumor targeting imaging system by simply fabricating a tumor-homing penetration peptide iRGD (CRGDKGPDC) to red shift emissive CDs (iRGD-CDs) with a physical method. Particularly, iRGD-CDs showed a small size and red shift fluorescence signals as CDs, which made iRGD-CDs suitable for in vivo fluorescence imaging. iRGD-CDs showed higher cellular uptake in vitro, while presented higher penetration and accumulation in tumor tissue in vivo, leading to better tumor imaging efficacy. In conclusion, decoration with iRGD could significantly increase the permeability of CDs in tumor vessels and tumor tissue, generating more CDs leaking out from tumor vasculature, consequently improving the sensitivity of tumor imaging.

Near infrared quantum dots in biomedical applications: current status and future perspective

To address the requirements of biomedical applications including biosensing, bioimaging, and drug delivery, fluorescent nanomaterials served as efficient tools in many cases. Among them, near-infrared quantum dots (NIR QDs) have been used as novel fluorescent labels for their binary advantages of both QDs and NIR light. In this review, through collecting references in recent 10 years, we have introduced basic structures and properties of NIR QDs and summarized the classification and the related synthetic methods. This review also highlights the functionalization and surface bioconjugation of NIR QDs, and their biomedical applications in biosensing, bioimaging, and drug delivery. This article is categorized under: Diagnostic Tools > Diagnostic Nanodevices Diagnostic Tools > In Vitro Nanoparticle-Based Sensing Diagnostic Tools > In Vivo Nanodiagnostics and Imaging.

Ratiometric fluorescent sensing of copper ion based on chromaticity change strategy

AbstractCopper ions play a significant role in human bodies, as they are beneficial for many metabolism processes, but excessive Cu2+ may cause various symptoms. Therefore, the development of strategies capable of both sensitive detection and visualization of Cu2+ is greatly important for human health. In this work, a novel ratiometric fluorescence sensor for rapid and visual detection of Cu2+ was designed based on green emission carbon dots (CDs) and red emission CdTe/CdS quantum dots (QDs). We have calculated the chromaticity coordinates of individual CDs and CdTe/CdS QDs, and the chromaticity coordinate of their mixture would change along the line between the two points of CDs and CdTe/CdS QDs in the chromaticity coordinate system. The red fluorescence of QDs can be influenced by Cu2+, and the fluorescence color of CDs-QDs changes from yellow to green as the chromaticity coordinates change with the addition of Cu2+. This traffic-light-type color change was more sensitive to the naked eye compared to conventional single emission-based sensors. This paper not only realized ratiometric fluorescence and visual detection of Cu2+ through a convenient method but also provided a promising strategy of designing an assay kit for trace Cu2+. Graphical abstractRatiometric fluorescent sensing of copper ion based on chromaticity change strategy

Recent Advances in Synthesis and Identification of Cyclic Peptides for Bioapplications

Cyclic peptides, owing to their good stability, high resistance to exo- and to some extent endo-peptidases, enhanced binding affinity and selectivity towards target biomolecules, are actively investigated as biochemical tools and therapeutic agents. In this review, we discuss various commonly utilized synthetic strategies for cyclic peptides and peptoids (peptidomimetics), their important screening methods to identify the bioactive cyclic peptides and peptoids such as combinatorial beadbased peptide library, phage display, mRNA display etc. and recent advances in their applications as bioactive compounds. Lastly, we also make a summary and provide an outlook of the research area.

Platinum(IV) prodrugs with long lipid chains for drug delivery and overcoming cisplatin resistance

Platinum(iv) prodrugs of clinically used cisplatin and oxaliplatin with two axial long lipid chains were developed for nanoparticle delivery to combat cisplatin resistance.

Photoluminescence mechanism and applications of Zn-doped carbon dots

Heteroatom-doped carbon dots (CDs) with excellent optical characteristics and negligible toxicity have emerged in many applications including bioimaging, biosensing, photocatalysis, and photothermal therapy. The metal-doping of CDs using various heteroatoms results in an enhancement of the photophysics but also imparts them with multifunctionality. However, unlike nonmetal doping, typical metal doping results in low fluorescence quantum yields (QYs), and an unclear photoluminescence mechanism. In this contribution, we detail results concerning zinc doped CDs (Zn-CDs) with QYs of up to 35%. The zinc ion charges serve as a surface passivating agent and prevent the aggregation of graphene π–π stacking, leading to an increase in the QY of the Zn-CDs. Structural and chemical investigations using spectroscopic and first principle simulations further revealed the effects of zinc doping on the CDs. The robust Zn-CDs were used for the ultra-trace detection of Hg2+ with a detection limit of 0.1 μM, and a quench mechanism was proposed. The unique optical properties of the Zn-CDs have promise for use in applications such as in vivo sensing and future phototherapy applications.

Organosilicon modification to enhance the stability of black phosphorus nanosheets under ambient conditions

Thanks to its tunable direct band gap, high charge-carrier mobility, and unique in-plane anisotropic structure, black phosphorus (BP) has become a rising star among post-graphene two-dimensional (2D) nanomaterials. However, BP is unstable under ambient conditions, which largely limits its application. In this paper, an organosilicon agent, TMSCl, was used for the surface coordination of BP nanosheets to generate TMSCl@BP, which could maintain its surface morphology and properties for 24 h under ambient conditions and has no cytotoxicity at a concentration of 200 ppm as per previous reports. Our study is the first evidence that bare BP can coordinate with organosilicon to generate the more stable TMSCl@BP. Notably, the photothermal effect of TMSCl@BP was maintained after exposure to ambient conditions for over 24 hours.