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The detection of nucleic acids and their mutation derivatives is vital for biomedical science and applications. Although many nucleic acid biosensors have been developed, they often require pretreatment processes, such as target amplification and tagging probes to nucleic acids. Moreover, current biosensors typically cannot detect sequence-specific mutations in the targeted nucleic acids. To address the above problems, herein, we developed an electrochemical nanobiosensing system using a phenomenon comprising metal ion intercalation into the targeted mismatched double-stranded nucleic acids and a homogeneous Au nanoporous electrode array (Au NPEA) to obtain (i) sensitive detection of viral RNA without conventional tagging and amplifying processes, (ii) determination of viral mutation occurrence in a simple detection manner, and (iii) multiplexed detection of several RNA targets simultaneously. As a proof-of-concept demonstration, a SARS-CoV-2 viral RNA and its mutation derivative were used in this study. Our developed nanobiosensor exhibited highly sensitive detection of SARS-CoV-2 RNA (∼1 fM detection limit) without tagging and amplifying steps. In addition, a single point mutation of SARS-CoV-2 RNA was detected in a one-step analysis. Furthermore, multiplexed detection of several SARS-CoV-2 RNAs was successfully demonstrated using a single chip with four combinatorial NPEAs generated by a 3D printing technique. Collectively, our developed nanobiosensor provides a promising platform technology capable of detecting various nucleic acids and their mutation derivatives in highly sensitive, simple, and time-effective manners for point-of-care biosensing. 

Stem cells show excellent potential in the field of tissue engineering and regenerative medicine based on their excellent capability to not only self-renew but also differentiate into a specialized cell type of interest. However, the lack of a non-destructive monitoring system makes it challenging to identify and characterize differentiated cells before their transplantation without compromising cell viability. Thus, the development of a non-destructive monitoring method for analyzing cell function is highly desired and can significantly benefit stem cell-based therapies. Recently, nanomaterial-based scaffolds ( e.g. , nanoarrays) have made possible considerable advances in controlling the differentiation of stem cells and characterization of the differentiation status sensitively in real time. This review provides a selective overview of the recent progress in the synthesis methods of nanoarrays and their applications in controlling stem cell fate and monitoring live cell functions electrochemically. We believe that the topics discussed in this review can provide brief and concise guidelines for the development of novel nanoarrays and promote the interest in live cell study applications. A method which can not only control but also monitor stem cell fate and function will be a promising technology that can accelerate stem cell therapies. 

Abstract Nanoparticle‐based nucleic acid conjugates (NP‐NACs) hold great promise for theragnostic applications. However, several limitations have hindered the realization of their full potential in the clinical treatment of cancer and other diseases. In diagnoses, NP‐NACs suffer from low signal‐to‐noise ratios, while the efficiency of NP‐NACs‐mediated cancer therapies has been limited by the adaptation of alternative prosurvival pathways in cancer cells. The recent emergence of personalized and precision medicine has outlined the importance of having both accurate diagnosis and efficient therapeutics in a single platform. As such, the controlled assembly of hybrid graphene oxide/gold nanoparticle (Au@GO NP)‐based cancer‐specific NACs (Au@GO NP‐NACs) for multimodal imaging and combined therapeutics is reported. The developed Au@GO NP‐NACs show excellent surface‐enhanced Raman scattering (SERS)‐mediated live‐cell cancer detection and multimodal synergistic cancer therapy through the use of photothermal, genetic, and chemotherapeutic strategies. Synergistic and selective killing of cancer cells are then demonstrated using in vitro microfluidic models. Moreover, with the distinctive advantages of the Au@GO NP‐NACs for cancer theragnostics, precision cancer treatment through the detection of cancer cells in vivo using SERS followed by efficient ablation of tumors is shown. Therefore, the Au@GO NP‐NACs can pave a new road for advanced disease theragnostics.