A wearable electrostimulation-augmented ionic-gel photothermal patch doped with MXene for skin tumor treatment.

A wearable biological patch capable of producing multiple responses to light and electricity without interfering with daily activities is highly desired for skin cancer treatment, but remains a key challenge. Herein, the skin-mountable electrostimulation-augmented photothermal patch (eT-patch) comprising transparent ionic gel with MXene (Ti3C2Tx) doping is developed and applied for the treatment of melanoma under photostimulation at 0.5 W/cm2. The eT-patch designed has superior photothermal and electrical characteristics owing to ionic gels doped with MXene which provides high photothermal conversion efficiency and electrical conductivity as a medium. Simultaneously, the ionic gel-based eT-patch having excellent optical transparency actualizes real-time observation of skin response and melanoma treatment process under photothermal and electrical stimulation (PES) co-therapy. Systematical cellular study on anti-tumor mechanism of the eT-patch under PES treatment revealed that eT-patch under PES treatment can synergically trigger cancer cell apoptosis and pyroptosis, which together lead to the death of melanoma cells. Due to the obvious advantages of relatively safe and less side effects in healthy organs, the developed eT-patch provides a promising cost-effective therapeutic strategy for skin tumors and will open a new avenue for biomedical applications of ionic gels.

"Light-On" Fluorescent Nanoprobes for Monitoring Dynamic Distribution of Cellular Nucleolin During Pyroptosis.

Nucleolin (NCL) is a multifunctional nuclear protein that plays significant roles in regulating physiological activities of the cells. However, it remains a challenge to monitor the dynamic distribution and expression of nucleolin within living cells during cell stress processes directly. Here, we designed "turn-on" fluorescent nanoprobes composed of specific AS1411 aptamer and nucleus-targeting peptide on gold nanoparticles (AuNPs) to effectively capture and track the NCL distribution and expression during pyroptosis triggered by electrical stimulation (ES). The distribution of nucleolin in the cell membrane and nucleus can be easily observed by simply changing the particle size of the nanoprobes. The present strategy exhibits obvious advantages such as simple operation, low cost, time saving, and suitability for living cell imaging. The ES can induce cancer cell pyroptosis controllably and selectively, with less harm to the viability of normal cells. The palpable cell nuclear stress responses of cancerous cells, including nucleus wrinkling and nucleolus fusion after ES at 1.0 V were obviously observed. Compared with normal cells (MCF-10A), NCL is overexpressed within cancerous cells (MCF-7 cells) using the as-designed nanoprobes, and the ES can effectively inhibit NCL expression within cancerous cells. The developed NCL sensing platform and ES-based methods hold great potential for cellular studies of cancer-related diseases.

Label-Free Single-Cell SERS Detection and Fluorescence Imaging of Molecular Responses to Endoplasmic Reticulum Stress under Electrical Stimulation.

The endoplasmic reticulum (ER) is one of the most important organelles in eukaryotic cells, in which most proteins and lipids are synthesized to regulate complex cellular processes. Generally, the excessive accumulation of unfolded or misfolded proteins can disturb ER homeostasis and induce endoplasmic reticulum stress (ERS). Howbeit, the molecular stress responses within ERS and metastatic behaviors of tumor cells during electrical stimulation (ES) are still poorly investigated and remain a challenge. In this study, by the combined use of fluorescence imaging, ER-targeting plasmonic nanoprobes were developed to trace molecular stress response profiling within the ER during a constant-voltage ES process at ∼1 V based on label-free surface-enhanced Raman spectroscopy (SERS). The excess accumulation of ß-misfolded proteins was found after the ES, leading to breaking of the ER homeostasis and further inducing mitochondrial dysfunction. Notably, the excessive stress of ER under ES can destroy the calcium ion balance and induce significant upregulation of calreticulin expression. Importantly, the content ratio of two kinds of cadherin between E-cadherin and N-cadherin was gradually improved with the voltages boosted. Meanwhile, the epithelial adhesion factor expression was ascended with voltages amplified, leading to inhibiting tumor cell migration at low voltages or death under higher voltages (∼1 V). This study provides cellular insights into the ES approach for tumor therapy and also provides a simple and effective method for detecting molecular stress responses in endoplasmic reticulum stress.

Machine Learning-Based Label-Free SERS Profiling of Exosomes for Accurate Fuzzy Diagnosis of Cancer and Dynamic Monitoring of Drug Therapeutic Processes.

Exosomes are a class of extracellular vesicles secreted by cells, which can be used as promising noninvasive biomarkers for the early diagnosis and treatment of diseases, especially cancer. However, due to the heterogeneity of exosomes, it remains a grand challenge to distinguish accurately and reliably exosomes from clinical samples. Herein, we achieve accurate fuzzy discrimination of exosomes from human serum samples for accurate diagnosis of breast cancer and cervical cancer through machine learning-based label-free surface-enhanced Raman spectroscopy (SERS), by using "hot spot" rich 3D plasmonic AuNPs nanomembranes as substrates. Due to the existence of some weak distinguishable SERS fingerprint signals and the high sensitivity of the method, the machine learning-based SERS analysis can precisely identify three (normal and cancerous) cell lines, two of which are different types of cancer cells, without specific labeling of biomarkers. The prediction accuracy based on the machine learning algorithm was up to 91.1% for the discrimination of different cell lines (H8, HeLa, and MCF-7 cell)-derived exosomes. Our model trained with SERS spectra of cell-derived exosomes could reach 93.3% prediction accuracy for clinical samples. Furthermore, the action mechanism of the chemotherapeutic process of MCF-7 cells can be revealed by dynamic monitoring of SERS profiling of the exosomes secreted. The method would be useful for noninvasive and accurate diagnosis and postoperative assessment of cancer or other diseases in the future.

Label-Free SERS Detection of Protein Damage in Organelles under Electrostimulation with 2D AuNPs-based Nanomembranes as Substrates.

Proteins as the material basis of life are the main undertakers of life activities. However, it is difficult to identify the related proteins in organelles during stimuli-induced stress responses in cells and remains a great challenge in early diagnosis and treatment of disease. Here, proteins in the cell nucleus and mitochondria of cells under the electrical stimulation (ES) process were collected and sensitively detected based on label-free surface-enhanced Raman spectroscopy (SERS) by using AuNP-based nanomembranes as high-performance SERS substrates. Due to the existence of rich "hot spots" on the 2D plasmonic sensing platform, high-quality SERS spectra of proteins were obtained with superior sensitivity and repeatability. From the SERS analyses in vitro, it was found that the conformation of some proteins in the two kinds of organelles from cancerous HCT-116 cells (compared with normal NCM-460 cells) changed significantly and the expression levels of tyrosine, phenylalanine, and tryptophan were significantly promoted during the stimulation process. Although currently the exact proteins are still unknown, the damage of proteins in the organelles of cells at the amino acid level under ES can be revealed by the method. The developed plasmonic SERS sensing platform would be promising for bioassay and cell studies.

Plasmon-Boosted Fe, Co Dual Single-Atom Catalysts for Ultrasensitive Luminol-Dissolved O2 Electrochemiluminescence Detection of Prostate-Specific Antigen.

Improving the sensitivity of electrochemiluminescence (ECL) systems is highly desired for in vitro ECL diagnosis and bio-detections due to the often-low content of biomarkers in diseases. And dissolved O2 (DO) as a co-reactant is considered superior to H2O2 in the most commonly used luminol ECL systems due to better stability and low biotoxicity, but it still suffers from low ECL performance due to the low reactivity of DO. In this study, an efficient luminol-DO ECL system was developed through the complexing of Fe, Co dual single-atom catalysts (D-SACs) supported by N-doped graphene with the luminol-capped Ag nanoparticles (AgNPs). Benefiting from the electronic interaction between Fe and Co metal sites in the relevant D-SACs and plasmon enhancement of AgNPs, the performance of the corresponding ECL system could be significantly boosted up to ≈677-fold under optimal testing conditions, comparable to the classic luminol-O2 system. Furthermore, the developed luminol-DO ECL system was successfully applied for the stable ultrasensitive detection of prostate-specific antigen (PSA) in a wide linear range of 1 fg/mL to 1 µg/mL, with a low limit of detection (0.98 fg/mL).

Optoplasmonic Modulation of Cell Metabolic State Promotes Rapid Cell Differentiation.

Cell differentiation plays a vital role in mediating organ formation and tissue repair and regeneration. Although rapid and effective methods to stimulate cell differentiation for clinical purposes are highly desired, it remains a great challenge in the medical fields. Herein, a highly effective and conceptual optical method was developed based on a plasmonic chip platform (made of 2D AuNPs nanomembranes). through effective light-augmented plasmonic regulation of cellular bioenergetics (CBE) and an entropy effect at bionano interfaces, to promote rapid cell differentiation. Compared with traditional methods, the developed optoplasmonic method greatly shortens cell differentiation time from usually more than 10 days to only about 3 days. Upon the optoplasmonic treatment of cells, the conformational and vibration entropy changes of cell membranes were clearly revealed through theoretical simulation and fingerprint spectra of cell membranes. Meanwhile, during the treatment process, bioenergetics levels of cells were elevated with increasing mitochondrial membrane potential (Δψm), which accelerates cell differentiation and proliferation. The developed optoplasmonic method is highly efficient and easy to implement, provides a new perspective and avenue for cell differentiation and proliferation, and has potential application prospects in accelerating tissue repair and regeneration.

Mimic Peroxidase- and Bi2S3 Nanorod-Based Photoelectrochemical Biosensor for Signal-On Detection of Polynucleotide Kinase.

We demonstrate for the first time the development of a mimic peroxidase- and bismuth sulfide (Bi2S3) nanorod-based photoelectrochemical (PEC) biosensor for signal-on detection of polynucleotide kinase (PNK) on the basis of manganese-based mimic enzyme (MnME) catalytic precipitation. We use the hybrid film which consists of Bi2S3 nanorods and Au nanoparticles (AuNPs) as the immobilization matrix of capture probe. The capture probe on the modified electrode can specifically hybridize with the MnME@AuNPs-labeled signal probe to form the double-stranded DNA (dsDNA), generating a PEC biosensor. In the absence of PNK, MnME may stimulate the mimic enzyme catalytic precipitation onto the electrode surface, blocking the interfacial electron transfer and eventually leading to a low PEC signal. While in the presence of PNK, the dsDNA is phosphorylated and subsequently cleaved by lambda exonuclease to release the MnME@AuNPs conjugates from the electrode, leading to the decrease of catalytic precipitation on the surface of electrode and consequently the production of a high PEC signal. Notably, the MnME can be easily synthesized and possesses higher catalytic activity than the manganese-based mimic enzyme. This signal-on PEC biosensor exhibits high sensitivity with a detection limit of 1.27 × 10-5 U mL-1 and an extrembly large dynamic range of 5 orders of magnitude. Moreover, it can be applied for the screening of PNK inhibitors and accurate quantification of PNK activity in cancer cell extracts.