Surface-enhanced Raman scattering holography chip for rapid, sensitive and multiplexed detection of human breast cancer-associated MicroRNAs in clinical samples

Recent progress in Surface-Enhanced Raman Spectroscopy detection of biomarkers in liquid biopsy for breast cancer

Breast cancer is the most commonly diagnosed cancer in women globally and a leading cause of cancer-related mortality. However, current detection methods, such as X-rays, ultrasound, CT scans, MRI, and mammography, have their limitations. Recently, with the advancements in precision medicine and technologies like artificial intelligence, liquid biopsy, specifically utilizing Surface-Enhanced Raman Spectroscopy (SERS), has emerged as a promising approach to detect breast cancer. Liquid biopsy, as a minimally invasive technique, can provide a temporal reflection of breast cancer occurrence and progression, along with a spatial representation of overall tumor information. SERS has been extensively employed for biomarker detection, owing to its numerous advantages such as high sensitivity, minimal sample requirements, strong multi-detection ability, and controllable background interference. This paper presents a comprehensive review of the latest research on the application of SERS in the detection of breast cancer biomarkers, including exosomes, circulating tumor cells (CTCs), miRNA, proteins and others. The aim of this review is to provide valuable insights into the potential of SERS technology for early breast cancer diagnosis.

Diagnosis and treatment status of inoperable locally advanced breast cancer and the application value of inorganic nanomaterials

Locally advanced breast cancer (LABC) is a heterogeneous group of breast cancer that accounts for 10-30% of breast cancer cases. Despite the ongoing development of current treatment methods, LABC remains a severe and complex public health concern around the world, thus prompting the urgent requirement for innovative diagnosis and treatment strategies. The primary treatment challenges are inoperable clinical status and ineffective local control methods. With the rapid advancement of nanotechnology, inorganic nanoparticles (INPs) exhibit a potential application prospect in diagnosing and treating breast cancer. Due to the unique inherent characteristics of INPs, different functions can be performed via appropriate modifications and constructions, thus making them suitable for different imaging technology strategies and treatment schemes. INPs can improve the efficacy of conventional local radiotherapy treatment. In the face of inoperable LABC, INPs have proposed new local therapeutic methods and fostered the evolution of novel strategies such as photothermal and photodynamic therapy, magnetothermal therapy, sonodynamic therapy, and multifunctional inorganic nanoplatform. This article reviews the advances of INPs in local accurate imaging and breast cancer treatment and offers insights to overcome the existing clinical difficulties in LABC management.

SERS-based microdevices for use as in vitro diagnostic biosensors

Advances in surface-enhanced Raman scattering (SERS) detection have helped to overcome the limitations of traditional in vitro diagnostic methods, such as fluorescence and chemiluminescence, owing to its high sensitivity and multiplex detection capability. However, for the implementation of SERS detection technology in disease diagnosis, a SERS-based assay platform capable of analyzing clinical samples is essential. Moreover, infectious diseases like COVID-19 require the development of point-of-care (POC) diagnostic technologies that can rapidly and accurately determine infection status. As an effective assay platform, SERS-based bioassays utilize SERS nanotags labeled with protein or DNA receptors on Au or Ag nanoparticles, serving as highly sensitive optical probes. Additionally, a microdevice is necessary as an interface between the target biomolecules and SERS nanotags. This review aims to introduce various microdevices developed for SERS detection, available for POC diagnostics, including LFA strips, microfluidic chips, and microarray chips. Furthermore, the article presents research findings reported in the last 20 years for the SERS-based bioassay of various diseases, such as cancer, cardiovascular diseases, and infectious diseases. Finally, the prospects of SERS bioassays are discussed concerning the integration of SERS-based microdevices and portable Raman readers into POC systems, along with the utilization of artificial intelligence technology.

SERS-based methods for the detection of genomic biomarkers of cancer

Genomic biomarkers of cancer are based on changes in nucleic acids, which include abnormal expression levels of some miRNAs, point mutations in DNA sequences, and altered levels of DNA methylation. The presence of tumor-related nucleic acids in body fluids (blood, saliva, or urine) makes it possible to achieve a non-invasive early-stage cancer diagnosis. Currently existing techniques for the discovery of nucleic acids require complex, time-consuming, costly assays and have limited multiplexing abilities. Surface-enhanced Raman spectroscopy (SERS) is a vibrational spectroscopy technique that is able to provide molecular specificity combined with trace sensitivity. SERS has gained research attention as a tool for the detection of nucleic acids because of its promising potential: label-free SERS can decrease the complexity of assays currently used with fluorescence-based detection due to the absence of the label, while labeled SERS may outperform the gold standard in terms of the multiplexing ability. The first papers about SERS-based methods for the measurement of genomic biomarkers were written in 2008, and since then, more than 150 papers have been published. The aim of this paper is to review and evaluate the proposed SERS-based methods in terms of their level of development and their potential for liquid biopsy application, as well as to contribute to their further evolution by attracting research attention to the field. This goal will be reached by grouping, on the basis of their experimental protocol, all the published manuscripts on the topic and evaluating each group in terms of its limit of detection and applicability to real body fluids. Thus, the methods are classified according to their working principles into five main groups, including capture-based, displacement-based, sandwich-based, enzyme-assisted, and specialized protocols.

A dual-mode method for detection of miRNA based on the photoluminescence and resonance light scattering

MicroRNAs (miRNAs) hold potential as useful biomarkers for early diagnosis and evaluation of diverse cancers, but their low abundance and short length make the detection of miRNAs face low sensitivity and accuracy. Herein, a photoluminescence (PL)-resonance light scattering (RLS) dual-mode method was developed for the sensitive and accurate detection of miRNA-141 using CdTe quantum dots (QDs) and Au nanoparticles. The presence of miRNA-141 induced PL quenching and RLS increasing. The limit of detection (LOD) was as low as 3.7 fM, and the miRNA-141 was detected linearly in a range from 10 fM to 10 nM. The dual signals generated no mutual interference and were detected using the same spectrophotometer, allowing for mutual validation to ensure the accuracy and reliability of the detection results. This study proposes valuable references for constructing dual-mode detection methods.

Impact of Nanomedicine in Women's Metastatic Breast Cancer

Metastatic breast cancer is responsible for 90% of mortalities among women suffering from various types of breast cancers. Traditional cancer treatments such as chemotherapy and radiation therapy can cause significant side effects and may not be effective in many cases. However, recent advances in nanomedicine have shown great promise in the treatment of metastatic breast cancer. For example, nanomedicine demonstrated robust capacity in detection of metastatic cancers at early stages (i.e., before the metastatic cells leave the initial tumor site), which gives clinicians a timely option to change their treatment process (for example, instead of endocrine therapy they may use chemotherapy). Here recent advances in nanomedicine technology in the identification and treatment of metastatic breast cancers are reviewed.

A rapid and simple method for simultaneous determination of three breast cancer related microRNAs based on magnetic nanoparticles modified with S9.6 antibody

Cancer progression is typically associated with the simultaneous changes of multiple microRNA (miR) levels. Therefore, simultaneous determination of multiple miR biomarkers exhibits great promise in early diagnosis of cancers. This research seeks to discuss a simple biosensing method for the ultrasensitive and specific detection of the three miRs related to the breast cancer based on S9.6 antibody coated magnetic beads, titanium phosphate nanospheres, and screen-printed carbon electrode. To prepare signaling probes, three hairpin DNAs (hDNAs) were labeled with three encoding titanium phosphate nanospheres with large quantities of different heavy metal ions (zinc, cadmium, lead), which have been utilized to discriminate the signals of three microRNA targets in relation with the corresponding heavy metal ions. After that, these hairpin structures hybridize with miR-21, miR-155 and miR-10b to form miR-21/hDNA1, miR-155/hDNA2 and miR-10b/hDNA3 complexes, which were captured by S9.6 antibodies (one anti-DNA/RNA antibody) pre-modified on magnetic bead surface. Therefore, the specific preconcentration of targets from complex matrixes can be carried out using magnetic actuation, increasing the sensitivity and specificity of the detection. The biosensor was suitably applied for direct and rapid detection of multiple microRNAs in real sample. It was observed that there were no significant differences between the results obtained by the suggested method and qRT-PCR as a reference method. So, this method makes an ultrasensitive novel platform for miRNAs expression profiling in clinical diagnosis and biomedical research.

Recent Trends in SERS-Based Plasmonic Sensors for Disease Diagnostics, Biomolecules Detection, and Machine Learning Techniques

Surface-enhanced Raman spectroscopy/scattering (SERS) has evolved into a popular tool for applications in biology and medicine owing to its ease-of-use, non-destructive, and label-free approach. Advances in plasmonics and instrumentation have enabled the realization of SERS's full potential for the trace detection of biomolecules, disease diagnostics, and monitoring. We provide a brief review on the recent developments in the SERS technique for biosensing applications, with a particular focus on machine learning techniques used for the same. Initially, the article discusses the need for plasmonic sensors in biology and the advantage of SERS over existing techniques. In the later sections, the applications are organized as SERS-based biosensing for disease diagnosis focusing on cancer identification and respiratory diseases, including the recent SARS-CoV-2 detection. We then discuss progress in sensing microorganisms, such as bacteria, with a particular focus on plasmonic sensors for detecting biohazardous materials in view of homeland security. At the end of the article, we focus on machine learning techniques for the (a) identification, (b) classification, and (c) quantification in SERS for biology applications. The review covers the work from 2010 onwards, and the language is simplified to suit the needs of the interdisciplinary audience.

CRISPR Cas12a-Powered Silicon Surface-Enhanced Raman Spectroscopy Ratiometric Chip for Sensitive and Reliable Quantification

Sensitive and reliable clustered regularly interspaced short palindromic repeats (CRISPR) quantification without preamplification of the sample remains a challenge. Herein, we report a CRISPR Cas12a-powered silicon surface-enhanced Raman spectroscopy (SERS) ratiometric chip for sensitive and reliable quantification. As a proof-of-concept application, we select the platelet-derived growth factor-BB (PDGF-BB) as the target. We first develop a microfluidic synthetic strategy to prepare homogeneous silicon SERS substrates, in which uniform silver nanoparticles (AgNPs) are in situ grown on a silicon wafer (AgNPs@Si) by microfluidic galvanic deposition reactions. Next, one 5'-SH-3'-ROX-labeled single-stranded DNA (ssDNA) is modified on AgNPs via Ag-S bonds. In our design, such ssDNA has two fragments: one fragment hybridizes to its complementary DNA (5'-Cy3-labeled ssDNA) to form double-stranded DNA (dsDNA) and the other fragment labeled with 6'-carboxy-X-rhodmine (ROX) extends out as a substrate for Cas12a. The cleavage of the ROX-tagged fragment by Cas12a is controlled by the presence or not of PDGF-BB. Meanwhile, Cy3 molecules serving as internal standard molecules still stay at the end of the rigid dsDNA, and their signals remain constant. Thereby, the ratio of ROX signal intensity to Cy3 intensity can be employed for the reliable quantification of PDGF-BB concentration. The developed chip features an ultrahigh sensitivity (e.g., the limit of detection is as low as 3.2 pM, approximately 50 times more sensitive than the fluorescence counterpart) and good reproducibility (e.g., the relative standard deviation is less than 5%) in the detection of PDGF-BB.

Trends in Application of SERS Substrates beyond Ag and Au, and Their Role in Bioanalysis

This article compares the applications of traditional gold and silver-based SERS substrates and less conventional (Pd/Pt, Cu, Al, Si-based) SERS substrates, focusing on sensing, biosensing, and clinical analysis. In recent decades plethora of new biosensing and clinical SERS applications have fueled the search for more cost-effective, scalable, and stable substrates since traditional gold and silver-based substrates are quite expensive, prone to corrosion, contamination and non-specific binding, particularly by S-containing compounds. Following that, we briefly described our experimental experience with Si and Al-based SERS substrates and systematically analyzed the literature on SERS on substrate materials such as Pd/Pt, Cu, Al, and Si. We tabulated and discussed figures of merit such as enhancement factor (EF) and limit of detection (LOD) from analytical applications of these substrates. The results of the comparison showed that Pd/Pt substrates are not practical due to their high cost; Cu-based substrates are less stable and produce lower signal enhancement. Si and Al-based substrates showed promising results, particularly in combination with gold and silver nanostructures since they could produce comparable EFs and LODs as conventional substrates. In addition, their stability and relatively low cost make them viable alternatives for gold and silver-based substrates. Finally, this review highlighted and compared the clinical performance of non-traditional SERS substrates and traditional gold and silver SERS substrates. We discovered that if we take the average sensitivity, specificity, and accuracy of clinical SERS assays reported in the literature, those parameters, particularly accuracy (93-94%), are similar for SERS bioassays on AgNP@Al, Si-based, Au-based, and Ag-based substrates. We hope that this review will encourage research into SERS biosensing on aluminum, silicon, and some other substrates. These Al and Si based substrates may respond efficiently to the major challenges to the SERS practical application. For instance, they may be not only less expensive, e.g., Al foil, but also in some cases more selective and sometimes more reproducible, when compared to gold-only or silver-only based SERS substrates. Overall, it may result in a greater diversity of applicable SERS substrates, allowing for better optimization and selection of the SERS substrate for a specific sensing/biosensing or clinical application.

Dual signal magnification for ultrasensitive biosensing based on well-regulated SERS of AuNTs@AuHg and DSN-assisted amplification

AuNTs@AuHg alloy with well-regulated SERS properties was proposed, which displayed wonderful SERS intensity and effective salt resistance. Using miRNA-21 as a model analyte and combining with DSN-assisted amplification, a dual signal amplification strategy for ultrasensitive miRNA biosensing with a low detection limit (0.53 fM) and satisfactory selectivity was designed.

Surface-enhanced Raman scattering biosensors for detection of oncomiRs in breast cancer

Surface-enhanced Raman scattering (SERS) has emerged as one of the most promising platforms for various biosensing applications. These sensing systems encompass the advantages of specificity, ultra-high sensitivity, stability, low cost, repeatability, and easy-to-use methods. Moreover, their ability to offer a molecular fingerprint and identify the target analyte at low levels make SERS a promising technique for detecting circulating cancer biomarkers with greater sensitivity and reliability. Among the various circulating biomolecules, oncomiRs are emerging as prominent biomarkers for the early screening of breast cancers (BCs). In this review, we provide a comprehensive understanding of different SERS-based biosensors and their application to identify BC-specific oncomiRs. We also discuss different SERS-based sensing strategies, nano-analytical frameworks, and challenges to be addressed for effective clinical translation.

Ultrasensitive and Visual Electrochemiluminescence Ratiometry Based on a Constant Resistor-Integrated Bipolar Electrode for MicroRNA Detection

In this work, a new electrochemiluminescence (ECL) platform was constructed for detecting the prostate cancer marker microRNA-141 (miRNA-141) on a constant resistor-integrated closed bipolar electrode (BPE). It consisted of two reservoirs and a constant resistor, and both ends were connected to the anode of the driving electrode and the cathode of BPE. The cathode of BPE was modified with boron nitride quantum dots (BNQDs), and the anode reservoir was the [Ru(bpy)₃](PF₆)₂/TPrA system. After introducing a certain amount of hairpin DNA 3 (H3) and ferrocene-labeled single-stranded DNA (Fc-ssDNA) on the surface of the BNQDs, the ECL emission signal of the BNQDs was difficult to be observed by the naked eye, while [Ru(bpy)₃](PF₆)₂ emitted a strong and visible ECL signal. In the presence of the target, bipedal DNA assembled by catalytic hairpin assembly (CHA) took away the Fc-ssDNA and the ECL intensity of the BNQDs was enlarged, and as the concentration of miRNA-141 increased to the cutoff value, yellow-green light was visible by the naked eye. Meanwhile, the red emission signal of [Ru(bpy)₃](PF₆)₂/TPrA became weakened. Thus, an ultrasensitive "color switch" ECL biosensor for detection of miRNA-141 was constructed and endowed with a wide linear range from 10^-17 to 10^-7 M and a detection limit of 10^-17 M (S/N = 3). This study provides the potential for investigating portable devices in the detection of low-concentration nucleic acids.

Inter-coffee-ring effects boost rapid and highly reliable SERS detection of TPhT on a light-confining structure

Triphenyltin chloride (TPhT) is a widely applied toxic compound that poses a significant threat to humans and the environment. Surface-enhanced Raman spectroscopy (SERS), capable of non-destructive, rapid, and trace detection, is desirable to better evaluate its distribution and content. However, a sensitive method with simple measuring protocols which maintains excellent reproducibility remains challenging. Here, we proposed an inter-coffee-ring effect to accelerate the sampling and measuring process while maintaining highly reproducible results. Two overlapping coffee-rings are formed through sequenced drying of gold nanorod colloids and a gold nanorod TPhT mixture on a superhydrophobic light-confining structure. Both the gold nanorods and the TPhT are enriched in the overlapping region. The gold nanorods reordered in such an area under the inter-coffee-ring effect yielded vast numbers of consistent hotspots at the sub-2 nm level. Such consistency leads to excellent SERS performance under the light-confining effect induced by the nanoarray substrates. The detection limits of the probe molecule R6G reached 10⁻¹² M, and TPhT reached 10⁻⁸ M while achieving excellent stability and reproducibility, and a linear regression coefficient above 0.99 was achieved for TPhT. Crucially, the visible nature of the inter-coffee-ring overlap enabled rapid measurements, thus providing robust support for detecting environmental pollutants.

Nanoparticles reassembling in the inter coffee-ring region simply through sequenced drying of two droplets enabled ultrasensitive and highly reliable SERS detection. A rapid test protocol is realized by exciting the visible inter-coffee-ring mark.

From Raman to SESORRS: moving deeper into cancer detection and treatment monitoring

Raman spectroscopy is a non-invasive technique that allows specific chemical information to be obtained from various types of sample. The detailed molecular information that is present in Raman spectra permits monitoring of biochemical changes that occur in diseases, such as cancer, and can be used for the early detection and diagnosis of the disease, for monitoring treatment, and to distinguish between cancerous and non-cancerous biological samples. Several techniques have been developed to enhance the capabilities of Raman spectroscopy by improving detection sensitivity, reducing imaging times and increasing the potential applicability for in vivo analysis. The different Raman techniques each have their own advantages that can accommodate the alternative detection formats, allowing the techniques to be applied in several ways for the detection and diagnosis of cancer. This feature article discusses the various forms of Raman spectroscopy, how they have been applied for cancer detection, and the adaptation of the techniques towards their use for in vivo cancer detection and in clinical diagnostics. Despite the advances in Raman spectroscopy, the clinical application of the technique is still limited and certain challenges must be overcome to enable clinical translation. We provide an outlook on the future of the techniques in this area and what we believe is required to allow the potential of Raman spectroscopy to be achieved for clinical cancer diagnostics.

Recent Advances on Functional Nucleic-Acid Biosensors

In the past few decades, biosensors have been gradually developed for the rapid detection and monitoring of human diseases. Recently, functional nucleic-acid (FNA) biosensors have attracted the attention of scholars due to a series of advantages such as high stability and strong specificity, as well as the significant progress they have made in terms of biomedical applications. However, there are few reports that systematically and comprehensively summarize its working principles, classification and application. In this review, we primarily introduce functional modes of biosensors that combine functional nucleic acids with different signal output modes. In addition, the mechanisms of action of several media of the FNA biosensor are introduced. Finally, the practical application and existing problems of FNA sensors are discussed, and the future development directions and application prospects of functional nucleic acid sensors are prospected.