Undesired Cell Research Articles

Synthesis and In Vitro Antileishmanial Efficacy of Novel Ethylene Glycol Analogues of Benzothiadiazine-1,1-dioxide.

Leishmaniasis is a vector-borne, parasitic disease affecting millions of people and animals worldwide. Current therapeutic options have proven to be ineffective in both treating the disease and preventing its spread. As a result, new drugs must be developed to effectively combat this disease. In this study, a series of 14 ethylene glycol analogues of benzothiadiazine-1,1-dioxide were synthesised to investigate their antileishmanial potential and cytotoxicity. Analogue 9, 2-(2-phenoxyethyl)-2H-benzo[e][1,2,4]thiadiazine-1,1-dioxide, was identified as the most inhibitory compound as it was observed to moderately inhibit the growth of L. major (IC50 103 μM) and L. donovani (IC50 153 μM) promastigotes. However, in general, the series presented with low biological activity, which may be attributed to reduced target affinity and/or undesired cell culture protein binding.

Enhance the Performance of CZTSSe Solar Cells Through Inhibiting the Cu2+, Tu, and (─COOH) Association Reaction.

The Sol-gel precursor solution reaction mechanism has a significant impact on the Cu2ZnSn(S, Se)4 (CZTSSe) solar cells. It is discovered that in the Cu2ZnSnS4 (CZTS) precursor solution (CZTS-PS) in the preparation, there is an association reaction among Cu2+, thiourea (Tu), and carboxyl (-COOH), which is an important reason for the undesirable CZTSSe solar cells. The strong association reaction generates excessive Cu2+ ions, forming the CuxSe secondary phase on the surface of the CZTSSe absorber. The secondary phase causes a short circuit and deterioration of gadget performance. Following a 6-h aging period for the CZTS-PS, the average photoelectric conversion efficiency (PCE) of the device is enhanced to 8.02%, and there is also an improvement in device uniformity, as evidenced by a decrease in the standard deviation to less than 1. To inhibit the association reaction and eliminate the aging time phenomenon, a strategy is developed using hydrochloric acid to regulate the CZTS-PS environment. This strategy shifts the REDOX reaction in Cu2++Sn2+ toward the formation of Cu1++Sn4+, leading to a decrease in the defect concentrations of VSn(-/0) and CuSn(-/0), which increases the carrier concentration and reduces the impact of band tailing. The average power conversion efficiency (PCE) of the devices improved from 7.45% to 9.26%, the PCE of the best-performing CZTSSe solar cells increased from 9.25% to 9.83%, and the consistency among the devices is further enhanced, as indicated by a reduction in the standard deviation from 0.98 to 0.44. Ultimately, the device performance of the Cu2++Sn2+-DMF system improved by 11.01% (without the MgF2 layer) after optimization. This study serves as a reference for regulating the environment of the CZTS-PS to further enhance the CZTSSe devices' performance, and the photoelectric conversion efficiency is improved by ≈30%.

When Do Tumours Develop? Neoplastic Processes Across Different Timescales: Age, Season and Round the Circadian Clock.

While it is recognised that most, if not all, multicellular organisms harbour neoplastic processes within their bodies, the timing of when these undesirable cell proliferations are most likely to occur and progress throughout the organism's lifetime remains only partially documented. Due to the different mechanisms implicated in tumourigenesis, it is highly unlikely that this probability remains constant at all times and stages of life. In this article, we summarise what is known about this variation, considering the roles of age, season and circadian rhythm. While most studies requiring that level of detail be done on humans, we also review available evidence in other animal species. For each of these timescales, we identify mechanisms or biological functions shaping the variation. When possible, we show that evolutionary processes likely played a role, either directly to regulate the cancer risk or indirectly through trade-offs. We find that neoplastic risk varies with age in a more complex way than predicted by early epidemiological models: rather than resulting from mutations alone, tumour development is dictated by tissue- and age-specific processes. Similarly, the seasonal cycle can be associated with risk variation in some species with life-history events such as sexual competition or mating being timed according to the season. Lastly, we show that the circadian cycle influences tumourigenesis in physiological, pathological and therapeutic contexts. We also highlight two biological functions at the core of these variations across our three timescales: immunity and metabolism. Finally, we show that our understanding of the entanglement between tumourigenic processes and biological cycles is constrained by the limited number of species for which we have extensive data. Improving our knowledge of the periods of vulnerability to the onset and/or progression of (malignant) tumours is a key issue that deserves further investigation, as it is key to successful cancer prevention strategies.

Reversible and effective cell cycle synchronization method for studying stage-specific investigations.

The cell cycle is a crucial process for cell proliferation, differentiation, and development. Numerous genes and proteins play pivotal roles at specific cell cycle stages to regulate these events precisely. Studying the stage-specific functions of the cell cycle requires accumulating cell populations at the desired cell cycle stage. Cell synchronization, achieved through the use of cell cycle kinase and protein inhibitors, is often employed for this purpose. However, suboptimal concentrations of these inhibitors can result in reduced efficiency, irreversibility, and undesirable cell cycle defects. In this study, we have optimized effective and reversible techniques to synchronize the cell cycle at each stage in human RPE1 cells, utilizing both fixed high-precision cell cycle identification methods and high-temporal live-cell imaging. These reproducible synchronization methods are invaluable for investigating the regulatory mechanisms specific to each cell cycle stage.

Topographical and histological analysis of keratinized mucosal grafts removal techniques an ex-vivo study in porcine mandibles

The aim of this study was to assess the surface and tissue quality of keratinized mucosa grafts (KMG) obtained using the conventional scalpel and mucotome techniques. This was an experimental in vitro/ex vivo study involving six porcine hemi-mandibles. Specimens were harvested using both the mucotome and conventional scalpel techniques, with randomization determining the choice of technique for tissue removal. The specimens were prepared following predefined laboratory protocols and subsequently subjected to optical microscopy for evaluating epithelial and connective tissue and scanning electron microscopy for topographical and 3D profilometry analysis. Tissues harvested using the mucotome exhibited a linear base and uniform thickness, along with the presence of submucosa and fibrous connective tissue, all of which are ideal for graft success. Differences in the surface characteristics of specimens obtained through the two techniques were observed during a comparative analysis of images obtained through both microscopy types. KMG obtained using the mucotome technique displayed greater uniformity and reduced undesirable cell presence compared to the scalpel technique, thereby enhancing the likelihood of success in soft tissue graft surgical procedures. This study provides valuable insights to oral healthcare professionals and may contribute to future research aimed at achieving more successful surgeries, shorter postoperative recovery times, reduced discomfort, and an overall more positive patient experience.

Mesendodermal cells fail to contribute to heart formation following blastocyst injection.

Blastocyst complementation offers an opportunity for generating transplantable whole organs from donor sources. Pluripotent stem cells (PSCs) have traditionally served as the primary donor cells due to their ability to differentiate into any type of body cell. However, the use of PSCs raises ethical concerns, particularly regarding their uncontrollable differentiation potential to undesired cell lineages such as brain and germline cells. To address this issue, various strategies have been explored, including the use of genetically modified PSCs with restricted lineage potential or lineage-specified progenitor cells as donors. In this study, we tested whether nascent mesendodermal cells (MECs), which appear during early gastrulation, can be used as donor cells. To do this, we induced Bry-GFP+ MECs from mouse embryonic stem cells (ESCs) and introduced them into the blastocyst. While donor ESCs gave rise to various regions of embryos, including the heart, Bry-GFP+ MECs failed to contribute to the host embryos. This finding suggests that MECs, despite being specified from PSCs within a few days, lack the capacity to assimilate into the developing embryo.

Shape-Versatile Fixed Cellular Materials for Multiple Target Immunomodulation.

Therapeutic cells are usually administered as living agents, despite the risks of undesired cell migration and acquisition of unpredictable phenotypes. Additionally, most cell-based therapies rely on the administration of single cells, often associated with rapid in vivo clearance. 3D cellular materials may be useful to prolong the effect of cellular therapies and offer the possibility of creating structural volumetric constructs. Here, the manufacturing of shape-versatile fixed cell-based materials with immunomodulatory properties is reported. Living cell aggregates with different shapes (spheres and centimeter-long fibers) are fixed using a method compatible with maintenance of structural integrity, robustness, and flexibility of 3D constructs.The biological properties of living cells can be modulated before fixation, renderingan in vitroanti-inflammatory effect toward human macrophages, in line with a decreased activation of the nuclear factor kappa B (NF-κB) pathway that preponderantly correlated with the surface area of the materials. These findings are further corroborated in vivo in mouse skin wounds. Contact with fixed materials also reduces the proliferation ofactivated primary T lymphocytes, while promotingregulatory populations. The fixation of cellular constructs is proposed as a versatile phenotypic stabilization method that can be easily implemented to prepare immunomodulatory materials with therapeutic potential.

Coumarin-poly(2-oxazoline)s as synergetic and protein-undetected nanovectors for photodynamic therapy

Because of the difficult challenges of nanopharmaceutics, the development of a variety of nanovectors is still highly desired. Photodynamic therapy, which uses a photosensitizer to locally produce reactive oxygen species to kill the undesired cells, is a typical example for which encapsulation has been shown to be beneficial. The present work describes the use of coumarin-functionalized polymeric nanovectors based on the self-assembly of amphiphilic poly(2-oxazoline)s. Encapsulation of pheophorbide a, a known PDT photosensitizer, is shown to lead to an increased efficiency compared to the un-encapsulated version. Interestingly, the presence of coumarin both enhances the desired photocytotoxicity and enables the crosslinking of the vectors. Various nanovectors are examined, differing by their size, shape and hydrophilicity. Their behaviour in PDT protocols on HCT-116 cells monolayers is described, the influence of their crosslinking commented. Furthermore, the formation of a protein corona is assessed.

Action of photodynamic inactivation in antibiotic failures

SignificanceThe increase in the number of microorganisms resistant to antimicrobials motivates the search for strategies that recover the use of traditional antibiotics. Photodynamic Inactivation (PDI) is an alternative to antibiotics because the combination of a photosensitizer with light leads to the production of reactive oxygen species that promote the elimination of undesirable cells. ApproachCurcumin and light at 450 nm are applied at regular intervals and new values of minimum inhibitory concentration of antibiotics are obtained. ResultsWe demonstrated that the application of PDI reduces the necessary dosage of antibiotics for the elimination of the bacterial cell, proving to be an efficient strategy for application in resistant strains. Furthermore, we verified that the interaction of the photosensitizer with the antibiotics promotes alterations in the metabolism and the bacterial biomolecules. ConclusionsThese results are essential to transfer in vitro studies to the clinical implementation of DIF as an adjuvant to antibiotic therapy.

Action of photodynamic inactivation in antibiotic failures

SignificanceThe increase in the number of microorganisms resistant to antimicrobials motivates the search for strategies that recover the use of traditional antibiotics. Photodynamic Inactivation (PDI) is an alternative to antibiotics because the combination of a photosensitizer with light leads to the production of reactive oxygen species that promote the elimination of undesirable cells. ApproachCurcumin and light at 450 nm are applied at regular intervals and new values of minimum inhibitory concentration of antibiotics are obtained. ResultsWe demonstrated that the application of PDI reduces the necessary dosage of antibiotics for the elimination of the bacterial cell, proving to be an efficient strategy for application in resistant strains. Furthermore, we verified that the interaction of the photosensitizer with the antibiotics promotes alterations in the metabolism and the bacterial biomolecules. ConclusionsThese results are essential to transfer in vitro studies to the clinical implementation of DIF as an adjuvant to antibiotic therapy.

Abstract 2668: CBO421: A novel drug Fc-conjugate to prevent tumor immune evasion via the CD73/adenosine pathway

Abstract Background CD73 (5’-nucleotidase or NT5E) is a cell surface enzyme responsible for the rate limiting step in adenosine production; the conversion of adenosine monophosphate (AMP) into adenosine. Adenosine contributes to immune evasion by solid tumors by concentrating immunosuppressive adenosine in the tumor microenvironment. CBO421, a Drug Fc-Conjugate (DFC), comprises a novel small molecule CD73 inhibitor stably conjugated to an immune-silent human IgG1 Fc, combining the strengths of small molecule inhibitors and CD73-targeting monoclonal antibodies (mAbs) for potential best-in-class efficacy. Methods CBO421’s binding affinity to human CD73 and Fc receptors was assessed by surface plasmon resonance. Antibody-dependent cellular cytotoxicity (ADCC) was evaluated using a commercial kit. Immunophenotyping and binding to cancer cells was measured by flow cytometry. Inhibition of soluble and membrane-bound CD73 on human PBMCs and mouse cancer cells was determined by measuring free phosphate levels. Functional activity was measured using PBMC rescue assays. In vivo efficacy of CBO421 monotherapy was evaluated in a syngeneic mouse model. Results CBO421 exhibited a binding affinity to human CD73 (KD = 0.8 nM) that was comparable to or greater to the affinity observed with small molecule inhibitors (AB680, OP-5244) and CD73-targeting mAbs (oleclumab, mupadolimab biosimilars). As expected, human FcRn binding of CBO421 was comparable to the unconjugated Fc and the full-length wild-type IgG1 control mAb. CBO421 binding to human Fc gamma receptors and ADCC activity was significantly reduced or abolished compared to the control mAb, such that it poses a minimal risk for undesired autoimmune activity. CBO421 potently inhibited soluble CD73 and CD73 expressed on human MDA-MB-231 and mouse EMT6 cancer cells. Immunophenotyping revealed that CD73 expression was primarily observed on CD8+ T and B cells from human PBMCs. In functional PBMC rescue assays, CBO421 demonstrated potent reactivation of AMP- or ATP-suppressed CD4+ or CD8+ T cells at levels comparable to small molecule inhibitors and greater than anti-CD73 mAb comparators. CBO421 monotherapy demonstrated a dose-dependent reduction in tumor volume in a syngeneic mouse model using MC38, a colorectal cancer cell line. Conclusions CBO421 exhibited strong binding and potent inhibition of both soluble and membrane-bound CD73, differentiating it from mAb CD73 inhibitors. The proprietary immune-silent Fc of CBO421 did not affect FcRn binding but substantially reduced Fc gamma receptor binding, leading to the elimination of ADCC activity to prevent undesired immune cell depletion in host tissues. CBO421 demonstrated high potency in functional cell-based assays and robust antitumor efficacy in a syngeneic mouse model. Currently, CBO421 is being advanced as a clinical development candidate for the treatment of solid cancers. Citation Format: Amanda Almaguer, Doug Zuill, Simon Döhrmann, James Levin, Nicholas Dedeic, Elizabeth Abelovski, Joanne Fortier, Qiping Zhao, Maria Hernandez, Karin Amundson, Madison Moniz, Hongyuan Chen, Dhanya Panickar, Thanh Lam, Tom Brady, Allen Borchardt, Grayson Hough, Jeffrey B. Locke, Jason N. Cole, Leslie W. Tari. CBO421: A novel drug Fc-conjugate to prevent tumor immune evasion via the CD73/adenosine pathway [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2668.

Combinatorial expression of γ-protocadherins regulates synaptic connectivity in the mouse neocortex.

In the process of synaptic formation, neurons must not only adhere to specific principles when selecting synaptic partners but also possess mechanisms to avoid undesirable connections. Yet, the strategies employed to prevent unwarranted associations have remained largely unknown. In our study, we have identified the pivotal role of combinatorial clustered protocadherin gamma (γ-PCDH) expression in orchestrating synaptic connectivity in the mouse neocortex. Through 5' end single-cell sequencing, we unveiled the intricate combinatorial expression patterns of γ-PCDH variable isoforms within neocortical neurons. Furthermore, our whole-cell patch-clamp recordings demonstrated that as the similarity in this combinatorial pattern among neurons increased, their synaptic connectivity decreased. Our findings elucidate a sophisticated molecular mechanism governing the construction of neural networks in the mouse neocortex.

Oxidative Stress, Endoplasmic Reticulum Stress and Apoptosis in the Pathology of Alzheimer's Disease.

Alzheimer's disease (AD) accounts for a major statistic among the class of neurodegenerative diseases. A number of mechanisms have been identified in its pathogenesis and progression which include the amyloid beta (Aβ) aggregation, hyperphosphorylation of tau protein, oxidative stress, endoplasmic reticulum (ER) stress and apoptosis. These processes are interconnected and contribute significantly to the loss of neurons, brain mass and consequential memory loss and other cognitive difficulties. Oxidative stress in AD appears to be caused by excess of oxygen free radicals and extracellular Aβ deposits that cause local inflammatory processes and activate microglia, another possible source of reactive oxygen species (ROS). ER Stress describes the accumulation of misfolded and unfolded proteins as a result of physiological and pathological stimuli including high protein demand, toxins, inflammatory cytokines, and mutant protein expression that disturbs ER homeostasis. When compared to age-matched controls, postmortem brain tissues from AD patients showed elevated levels of ER stress markers, such as PERK, eIF2α, IRE1α, the chaperone Grp78, and the downstream mediator of cell death CHOP. Apoptosis is in charge of eliminating unnecessary and undesired cells to maintain good health. However, it has been demonstrated that a malfunctioning apoptotic pathway is a major factor in the development of certain neurological and immunological problems and diseases in people, including neurodegenerative diseases. This article highlights and discussed some of the experimentally established mechanisms through which these processes lead to the development as well as the exacerbation of AD.

Resveratrol Alleviates the Early Challenges of Implant-Based Drug Delivery in a Human Glial Cell Model.

Brain diseases are oftentimes life-threatening and difficult to treat. The local administration of drug substances using brain implants can increase on-site concentrations and decrease systemic side effects. However, the biocompatibility of potential brain implant materials needs to be evaluated carefully as implants can trigger foreign body reactions, particularly by increasing the microglia and astrocyte reactivity. To date, these tests have been frequently conducted in very simple in vitro models, in particular not respecting the key players in glial cell reactions and the challenges of surgical implantation characterized by the disruption of oxygen and nutrient supply. Thus, we established an in vitro model in which we treated human glial cell lines with reduced oxygen and glucose levels. The model displayed cytokine and reactive oxygen species release from reactive microglia and an increase in a marker of reactive astrocytes, galectin-3. Moreover, the treatment caused changes in the cell survival and triggered the production of hypoxia-inducible factor 1α. In this comprehensive platform, we demonstrated the protective effect of the natural polyphenol resveratrol as a model substance, which might be included in brain implants to ease the undesired glial cell response. Overall, a glial-cell-based in vitro model of the initial challenges of local brain disease treatment may prove useful for investigating new therapy options.

Investigation of the effectiveness of gelatin hydrolysate in human iPS-RPE cell suspension transplantation

IntroductionThe retinal pigment epithelium (RPE) plays essential roles in maintaining retinal functions as well as choroidal capillaries and can lead to visual disorders if dysfunctional. Transplantation of human-induced pluripotent stem cell-derived RPE (hiPSC-RPE) is a promising therapy for such RPE impaired conditions including age-related macular degeneration. The challenge with cell suspension transplantation is targeted delivery of graft cells and undesired cell reflux. Gelatin hydrolysate, a soluble variant with specific molecular weight distribution, is examined in this study for its potential use in hiPSC-RPE suspension transplantation, particularly in reducing cell reflux and enhancing RPE engraftment. MethodsA retinal bleb model was created using polydimethylsiloxane (PDMS) soft lithography to quantify cellular reflux. We examined the effects of gelatin hydrolysate on the hiPSC-RPE of various aspects of cell behavior and performance such as cell viability, hypoxia reaction, morphology, induction of inflammation and immune responses. ResultsGelatin hydrolysate at 5 % concentration effectively mitigated cell reflux in vitro mimic, improved cell viability, reduced cell aggregation, and had an inhibitory effect on hypoxic reactions due to cell deposition with hiPSC-RPE. Additionally, gelatin hydrolysate did not affect cell adhesion and morphology, and decreased the expression of major histocompatibility complex class II molecules, which suggests reduced immunogenicity of hiPSC-RPE. ConclusionGelatin hydrolysate is considered a valuable and useful candidate for future regenerative therapies in hiPSC-RPE suspension transplantation.

Chemical synthetic approaches to mimic the TRAIL: promising cancer therapeutics.

Apoptosis is programmed cell death that eliminates undesired cells to maintain homeostasis in metazoan. Aberration of this process may lead to cancer genesis. The tumor necrosis factor related apoptosis inducing ligand (TRAIL) induces apoptosis in cancer cells after ligation with death receptors (DR4/DR5) while sparing most normal cells. Therefore, strategies to induce apoptosis in cancer cells by mimicking the TRAIL emerge as a promising therapeutic tool. Hence, approaches are taken to develop TRAIL/DR-based cancer therapeutics. The recombinant soluble TRAIL (rhTRAIL) and death receptor agonistic antibodies were produced and tested pre-clinically and clinically. Pre-clinical and clinical trial data demonstrate that these therapeutics are safe and relatively well tolerated. But some of these therapeutics failed to exert adequate efficacy in clinical settings. Besides these biotechnologically derived therapeutics, a few chemically synthesized therapeutics are reported. Some of these therapeutics exert considerable efficacy in vitro and in vivo. In this review, we will discuss chemically synthesized TRAIL/DR-based therapeutics, their chemical and biological behaviour, design concepts and strategies that may contribute to further improvement of TRAIL/DR-based therapeutics.

Uncovering a novel mechanism: Butyrate induces estrogen receptor alpha activation independent of estrogen stimulation in MCF-7 breast cancer cells.

Butyrate is a promising candidate for an antitumoral drug, as it promotes cancer cell apoptosis and reduces hormone receptor activity, while promoting differentiation and proliferation in normal cells. However, the effects of low-dose butyrate on breast cancer cell cultures are unclear. We explored the impact of sub-therapeutic doses of butyrate on estrogen receptor alpha (ERα) transcriptional activity in MCF-7 cells, using RT-qPCR, Western blot, wound-healing assays, and chromatin immunoprecipitation. Our results showed that sub-therapeutic doses of sodium butyrate (0.1 - 0.2 mM) increased the transcription of ESR1, TFF1, and CSTD genes, but did not affect ERα protein levels. Moreover, we observed an increase in cell migration in wound-healing assays. ChIP assays revealed that treatment with 0.1 mM of sodium butyrate resulted in estrogen-independent recruitment of ERα at the pS2 promoter and loss of NCoR. Appropriate therapeutic dosage of butyrate is essential to avoid potential adverse effects on patients' health, especially in the case of estrogen receptor-positive breast tumors. Sub-therapeutic doses of butyrate may induce undesirable cell processes, such as migration due to low-dose butyrate-mediated ERα activation. These findings shed light on the complex effects of butyrate in breast cancer and provide insights for research in the development of antitumoral drugs.

N-cadherin Alleviates Apoptosis and Senescence of Nucleus Pulposus Cells via Suppressing ROS-dependent ERS in the Hyper-osmolarity Microenvironment.

The in-situ osmolarity is an important physicochemical factor that regulates cell fate of nucleus pulposus cells (NPCs). Our previous studies demonstrated that reduced N-cadherin (NCDH) expression in nucleus pulposus cells is associated with cellular damage under hyper-osmolarity microenvironment. This study was aimed at exploring the impacts of NCDH on senescence and apoptosis of NPCs, as well as the potential molecular mechanism. By comparing NPCs from patients with lumbar fractures and lumbar disc herniation, we identified a correlation between decreased NCDH expression and increased endoplasmic reticulum stress (ERS), resulting in undesirable cell fate (senescence and apoptosis). After blocking Reactive oxygen species (ROS) or ERS, it was indicated that hyper-osmolarity microenvironment induced ERS was ROS-dependent. Further results demonstrated the correlation in rat NPCs. Upregulation of NCDH expression reduced ROS-dependent ERS, thus limiting undesirable cell fates in vitro. This was further confirmed through the rat tail acupuncture injection model. NCDH overexpression successfully mitigated ERS, preserved extracellular matrix production and alleviating intervertebral disc degeneration in vivo. Together, NCDH can alleviate senescence and apoptosis of NPCs by suppressing ROS-dependent ERS via the ATF4-CHOP signaling axis in the hyper-osmolarity microenvironment, thus highlighting the therapeutic potential of NCDH in combating degenerative disc diseases.

Manganese-based microcrystals equipped with Ythdf1-targeted biomimetic nanovaccines for reinforced dendritic cell spatiotemporal orchestration

Undesired dendritic cell (DC) spatiotemporal orchestration and innate immune stimulation severely dampens anti-tumor efficacy of cancer vaccines. Here, we develop a manganese-based (Mn2+) metal-organic framework (MOF) microcrystal equipped with Ythdf1-targeted biomimetic nanovaccines to create an in situ proinflammatory immune niche for augmented DC spatiotemporal orchestration. The bimetallic MOF microcrystal serves as a self-adjuvanting delivery platform that cannot only gradually release tumor-associated antigens and Mn2+, but also create an in situ immune niche for DC spatiotemporal orchestration including recruitment (particularly for DC1s, cross-presenting antigens to CD8+ T cells), activation, and lymph node migration. Benefitting from the Mn2+-mediated cGAS-STING activation together with Ythdf1 downregulation-induced antigen cross-presentation reinforcement, the vaccines elicit robust prophylactic efficacy for delaying B16-OVA and MC38 tumor occurrence, and show potent therapeutic efficacy for suppressing postoperative MC38 tumor recurrence and metachronous liver metastasis. Our study provides a versatile and powerful approach for fabricating personalized scaffold cancer vaccines.

Probing the Onset of the Bacterial Membrane Photodamage in Time using a Raman Optical Tweezer

Laser-induced photo damage of the optically confined microorganism is known to affect the bacterial membrane. We record the Raman spectra of a live, optically trapped Bacillus subtilis at different trapping time lapses to determine the changes in the bacterial membrane, which in turn impacts the flagellar rotation. A 1064 nm tightly focused laser traps a single de-flagellated bacterium and Surface Enhanced Raman Scattering (SERS) signals are recorded with silver nanoparticles (AgNPs) inserted into bacteria via the internal colloid method. The internal colloid method, albeit resulting in a modest signal increase, is employed in preference here to prevent undesirable cell aggregation or instabilities in trapping or compromised cell integrity resulting from the conventional nanoparticle dressing of the cell membrane. The second derivative of the Raman spectrum reveals subtle changes in the molecular structure of the bacterial membrane manifested by shifts in the phospholipid peak (1462 cm−1), amide III peak (1245 cm−1) and cytosine peak (792 cm−1), with increased trapping duration. This is followed by a Principal Component Analysis (PCA) to examine the changes occurring in the Raman spectral range (600 cm−1–1800 cm−1). By comparing the spectral shifts at specific time lapses from the moment of trapping, with the diminishing frequency of rotation of the body and flagella of the trapped flagellated counterpart bacterium at these same time lapses, we establish a direct correlation between the changes in membrane structure and compromised rotation of the bacterium during photodamage. Our results confirm that the subtle changes that occur at the biomolecular level in a cell when subjected to photodamage can be identified with good sensitivity, and moreover, that the changes occurring at the biomembrane have a role to play in reduced rotation of the trapped bacterium during exposure to the laser.