Smartphone-Based Device for Colorimetric Detection of MicroRNA Biomarkers Using Nanoparticle-Based Assay

Smartphones as a platform for molecular analysis: concepts, methods, devices and future potential

Over the past 15 years, smartphones have had a transformative effect on everyday life. These devices also have the potential to transform molecular analysis over the next 15 years. The cameras of a smartphone, and its many additional onboard features, support optical detection and other aspects of engineering an analytical device. This article reviews the development of smartphones as platforms for portable chemical and biological analysis. It is equal parts conceptual overview, technical tutorial, critical summary of the state of the art, and outlook on how to advance smartphones as a tool for analysis. It further discusses the motivations for adopting smartphones as a portable platform, summarizes their enabling features and relevant optical detection methods, then highlights complementary technologies and materials such as 3D printing, microfluidics, optoelectronics, microelectronics, and nanoparticles. The broad scope of research and key advances from the past 7 years are reviewed as a prelude to a perspective on the challenges and opportunities for translating smartphone-based lab-on-a-chip devices from prototypes to authentic applications in health, food and water safety, environmental monitoring, and beyond. The convergence of smartphones with smart assays and smart apps powered by machine learning and artificial intelligence holds immense promise for realizing a future for molecular analysis that is powerful, versatile, democratized, and no longer just the stuff of science fiction.

Cerium oxide mimetic enzyme based colorimetric detection of potential oesophageal cancer biomarkers

Oesophageal cancer (OC) is a prevalent malignant tumor that poses a significant threat to individuals. Current mainstream detection method is endoscopy, which requires professional operators and expensive instruments. Therefore, it is crucial to develop a rapid, easy-to-operate, and low-cost detection method. In this study, an RNA colorimetric biosensor was successfully constructed using cerium oxide mimetic enzyme. The sensor is constructed on 96-well plates, which are immobilized with DNA-RNA-DNA complexes in microtiter wells when target RNA is present. This immobilization is based on the principle of base complementary pairing. The CeO2 immobilized has the unique advantage of catalyzing the bluing of 3,3',5,5'-tetramethylbenzidine (TMB) directly without the need any additional oxidant in microtiter wells. This property allows for the detection of RNA and enables the visualization of multiple sample assays. Furthermore, the RNA colorimetric sensor demonstrates good selectivity, immunity to interference, and high stability. Under optimal conditions, the sensor exhibited linearity in the range of 10-13 to 10-9 M with a detection limit of 33.26 fM. Therefore, this study presents a new detection method for oesophageal cancer screening.

Recent advancements of smartphone-based sensing technology for diagnosis, food safety analysis, and environmental monitoring

The emergence of computationally powerful smartphones, relatively affordable high-resolution camera, drones, and robotic sensors have ushered in a new age of advanced sensible monitoring tools. The present review article investigates the burgeoning smartphone-based sensing paradigms, including surface plasmon resonance (SPR) biosensors, electrochemical biosensors, colorimetric biosensors, and other innovations for modern healthcare. Despite the significant advancements, there are still scarcity of commercially available smart biosensors and hence need to accelerate the rates of technology transfer, application, and user acceptability. The application/necessity of smartphone-based biosensors for Point of Care (POC) testing, such as prognosis, self-diagnosis, monitoring, and treatment selection, have brought remarkable innovations which eventually eliminate sample transportation, sample processing time, and result in rapid findings. Additionally, it articulates recent advances in various smartphone-based multiplexed bio sensors as affordable and portable sensing platforms for point-of-care devices, together with statistics for point-of-care health monitoring and their prospective commercial viability.

The Role of MicroRNAs in HIV Infection

MicroRNAs (miRNAs), a class of small, non-coding RNAs, play a pivotal role in regulating gene expression at the post-transcriptional level. These regulatory molecules are integral to many biological processes and have been implicated in the pathogenesis of various diseases, including Human Immunodeficiency Virus (HIV) infection. This review aims to cover the current understanding of the multifaceted roles miRNAs assume in the context of HIV infection and pathogenesis. The discourse is structured around three primary focal points: (i) elucidation of the mechanisms through which miRNAs regulate HIV replication, encompassing both direct targeting of viral transcripts and indirect modulation of host factors critical for viral replication; (ii) examination of the modulation of miRNA expression by HIV, mediated through either viral proteins or the activation of cellular pathways consequent to viral infection; and (iii) assessment of the impact of miRNAs on the immune response and the progression of disease in HIV-infected individuals. Further, this review delves into the potential utility of miRNAs as biomarkers and therapeutic agents in HIV infection, underscoring the challenges and prospects inherent to this line of inquiry. The synthesis of current evidence positions miRNAs as significant modulators of the host-virus interplay, offering promising avenues for enhancing the diagnosis, treatment, and prevention of HIV infection.

SERS-electrochemical dual-mode detection of microRNA on same interface assisted by exonuclease III signal transformation

Dual-mode sensing has attracted more attentions which provide more accurate and reliable approach of cancer-related biomarkers. Herein, we developed a novel SERS/electrochemical dual-mode biosensor for miRNA 21 detection based on Exo III-assisted signal transformation. Firstly, the Au NPs were deposited on electrode as SERS substrate and Mn3O4/S4(DNA signal strand) was modified on Au NPs/S5 by the DNA strands S5-S4 pairing principle as hydrogen peroxide catalyst, leading to an obviously high DPV electrical signal without Raman signal. Subsequently, the presence of miRNA 21 will activate the Mn3O4/S4 to be decomposed under exonuclease III-assisted process, then the S3' chains modified with Raman molecular Cy3(Cy3-S3') is continuously connected to the Au NPs/S5 by DNA stands S5-S3' pairing principle, leading to the Raman signal response and DPV signal reduction. The biosensor shows good linear calibration curves of both SERS and electrochemical sensing modes with the detection limit of 3.98 × 10-3 nM and 6.89 × 10-5 nM, respectively. This work finds an ingenious mode for dual detection of microRNA on a same interface, which opens a new strategy for SERS and electrochemical analysis.

Dual amplification-based ultrasensitive and highly selective colorimetric detection of miRNA

In this study, we combined a Pradeep Kumar (PK)-probe with a ligation-transcription-ramified RCA (LTR) dual-amplification system for the isothermal colorimetric detection of miRNA 25-3P, where the PK-probe transformed from its pink color to colorless in the presence of the amplification byproduct pyrophosphate (PPi), thereby allowing the simple naked-eye qualitative detection of the miRNA. Through this double-amplification strategy, the limit of detection reached as low as 91.4 aM-quite extraordinary sensitivity for a colorimetric miRNA detection system based on absorbance readings. Our detection system also operated with high specificity, the result of using two different target-selective ligation steps (linear DNA ligation and circular DNA ligation) mediated by SplintR ligase, and so could discriminate single-mismatched from perfectly matched target sequences. We suspect that this ultrasensitive and selective PK-probe/LTR dual-amplification system should be a great colorimetric diagnostic for the detection of any miRNA with high efficiency.

Colorimetric Sensors: Methods and Applications

Colorimetric sensors have attracted considerable attention in many sensing applications because of their specificity, high sensitivity, cost-effectiveness, ease of use, rapid analysis, simplicity of operation, and clear visibility to the naked eye [...].

Colorimetric Sensors for Chemical and Biological Sensing Applications

Colorimetric sensors have been widely used to detect numerous analytes due to their cost-effectiveness, high sensitivity and specificity, and clear visibility, even with the naked eye. In recent years, the emergence of advanced nanomaterials has greatly improved the development of colorimetric sensors. This review focuses on the recent (from the years 2015 to 2022) advances in the design, fabrication, and applications of colorimetric sensors. First, the classification and sensing mechanisms of colorimetric sensors are briefly described, and the design of colorimetric sensors based on several typical nanomaterials, including graphene and its derivatives, metal and metal oxide nanoparticles, DNA nanomaterials, quantum dots, and some other materials are discussed. Then the applications, especially for the detection of metallic and non-metallic ions, proteins, small molecules, gas, virus and bacteria, and DNA/RNA are summarized. Finally, the remaining challenges and future trends in the development of colorimetric sensors are also discussed.

Moving toward smart biomedical sensing

The development of novel biomedical sensors as highly promising devices/tools in early diagnosis and therapy monitoring of many diseases and disorders has recently witnessed unprecedented growth; more and faster than ever. Nonetheless, on the eve of Industry 5.0 and by learning from defects of current sensors in smart diagnostics of pandemics, there is still a long way to go to achieve the ideal biomedical sensors capable of meeting the growing needs and expectations for smart biomedical/diagnostic sensing through eHealth systems. Herein, an overview is provided to highlight the importance and necessity of an inevitable transition in the era of digital health/Healthcare 4.0 towards smart biomedical/diagnostic sensing and how to approach it via new digital technologies including Internet of Things (IoT), artificial intelligence, IoT gateways (smartphones, readers), etc. This review will bring together the different types of smartphone/reader-based biomedical sensors, which have been employing for a wide variety of optical/electrical/electrochemical biosensing applications and paving the way for future eHealth diagnostic devices by moving towards smart biomedical sensing. Here, alongside highlighting the characteristics/criteria that should be met by the developed sensors towards smart biomedical sensing, the challenging issues ahead are delineated along with a comprehensive outlook on this extremely necessary field.

NIR Photocontrolled Fluorescent Nanosensor under a Six-Branched DNA Nanowheel-Induced Nucleic Acid Confinement Effect for High-Performance Bioimaging

Although DNA nanotechnology is a promising option for fluorescent biosensors to perform bioimaging, the uncontrollable target identification during biological delivery and the spatially free molecular collision of nucleic acids may cause unsatisfactory imaging precision and sensitivity, respectively. Aiming at solving these challenges, we herein integrate some productive notions. On the one hand, the target recognition component is inserted with a photocleavage bond and a core-shell structured upconversion nanoparticle with a low thermal effect is further employed to act as the ultraviolet light generation source, under which a precise near-infrared photocontrolled sensing is achieved through a simple external 808 nm light irradiation. On the other hand, the collision of all of the hairpin nucleic acid reactants is confined by a DNA linker to form a six-branched DNA nanowheel, after which their local reaction concentrations are vastly enhanced (∼27.48 times) to induce a special nucleic acid confinement effect to guarantee highly sensitive detection. By selecting a lung cancer-associated short noncoding microRNA sequence (miRNA-155) as a model low-abundance analyte, it is demonstrated that the newly established fluorescent nanosensor not only presents good in vitro assay performance but also exhibits a high-performance bioimaging competence in live biosystems including cells and mouse body, propelling the progress of DNA nanotechnology in the biosensing field.

Paper-Based Colorimetric Detection of miRNA-21 Using Pre-Activated Nylon Membrane and Peroxidase-Mimetic Activity of Cysteamine-Capped Gold Nanoparticles

Irregular expression of MicroRNA-21 (miRNA-21) is considered as a promising biomarker for early cancer diagnosis. In this paper, a new genosensor based on paper and nanozyme activity of cysteamine-capped gold nanoparticles (Cys/AuNPs) was developed to detect picomolar concentrations of miRNA-21. Such nanozyme catalyzes the colorimetric reaction of hydrogen peroxide (H₂O₂) and 3,3',5,5' tetramethylbenzidine (TMB), to produce a blue color measurable by a smartphone. Due to their positive charge, Cys/AuNPs were attached to the negative phosphate groups of the DNA strand backbone via electrostatic interactions, leading to the quantitative determination of miRNA-21 concentration by the peroxidase-like activity of Cys/AuNPs. Furthermore, a paper-based assay was carried out on nylon disk devices to allow fast immobilization of DNA_probe. After performing the paper-based assay, a good linear range was observed between 1 pM and 1 nM (Y = 0.080 [MiRNA-21]/pM + 13.846, R² = 0.993) with a detection limit of 0.5 pM. The developed method was effective, selective, and sensitive for the miRNA-21 detection. The application of the proposed method for miRNA-21 detection was examined in a human serum sample, and a recovery rate of 90.0-97.6% was obtained showing the acceptable accuracy of the developed approach.

Poly(amidoamine) dendrimer immunosensor for ultrasensitive gravimetric and electrochemical detection of matrix metalloproteinase-9

Monitoring the level of matrix metalloproteinase-9 (MMP-9) and inhibiting its expression is important for the diagnosis and treatment of various diseases. However, the analysis of MMP-9 is challenging owing to its very low content in the blood, especially at the early stages of diseases. Therefore, we developed an ultrasensitive and easy-to-use immunosensor based on a three-dimensional (3D) bioplatform for the determination of the total MMP-9 concentration in plasma. The used 3D bioplatform (G2 poly(amidoamine) dendrimer; PAMAM) improved the sensitivity of the determination by significantly expanding the surface area of the receptor layer. The antigen-antibody recognition process was controlled by quartz crystal microbalance with dissipation (QCM-D) and electrochemical impedance spectroscopy (EIS). The effect of the orientation of antibody molecules in the sensing layer on the work parameters of the immunosensor was analyzed using unmodified PAMAM (PAMAM-NH₂) and PAMAM functionalized with -COOH groups (PAMAM-COOH). The developed immunosensor based on PAMAM-NH₂ was characterized by a lower detection limit (LOD = 2.0 pg⋅mL^-1) and wider analytical range (1·10^-4 - 5 μg⋅mL^-1 for EIS and QCM-D) compared to PAMAM-COOH immunosensor (EIS: 1·10^-4 - 0.5 μg⋅mL^-1; QCM-D: 5·10^-4 - 0.5 μg⋅mL^-1). The functionality of the proposed device was verified in spiked plasma. The recoveries determined in commercial human and rat plasma and noncommercial rat plasma were very close to the value of 100% and in the range of 96-120% for Au/PAMAM-NH₂/Ab and Au/PAMAM-COOH/Ab immunosensors, respectively. The designed analytical devices showed high selectivity and sensitivity without the use of any amplifiers such as metal nanoparticles or enzymes.

Application of Nanomaterials in the Prevention, Detection, and Treatment of Methicillin-Resistant Staphylococcus aureus (MRSA)

Due to differences in geographic surveillance systems, chemical sanitization practices, and antibiotic stewardship (AS) implementation employed during the COVID-19 pandemic, many experts have expressed concerns regarding a future surge in global antimicrobial resistance (AMR). A potential beneficiary of these differences is the Gram-positive bacteria MRSA. MRSA is a bacterial pathogen with a high potential for mutational resistance, allowing it to engage various AMR mechanisms circumventing conventional antibiotic therapies and the host’s immune response. Coupled with a lack of novel FDA-approved antibiotics reaching the clinic, the onus is on researchers to develop alternative treatment tools to mitigate against an increase in pathogenic resistance. Mitigation strategies can take the form of synthetic or biomimetic nanomaterials/vesicles employed in vaccines, rapid diagnostics, antibiotic delivery, and nanotherapeutics. This review seeks to discuss the current potential of the aforementioned nanomaterials in detecting and treating MRSA.

Nanoparticles in Clinical Translation for Cancer Therapy

The advent of cancer therapeutics brought a paradigm shift from conventional therapy to precision medicine. The new therapeutic modalities accomplished through the properties of nanomaterials have extended their scope in cancer therapy beyond conventional drug delivery. Nanoparticles can be channeled in cancer therapy to encapsulate active pharmaceutical ingredients and deliver them to the tumor site in a more efficient manner. This review enumerates various types of nanoparticles that have entered clinical trials for cancer treatment. The obstacles in the journey of nanodrug from clinic to market are reviewed. Furthermore, the latest developments in using nanoparticles in cancer therapy are also highlighted.