A cis-acting ligase ribozyme generates circular RNA in vitro for ectopic protein functioning.

Delivering synthetic protein-coding RNA bypassing the DNA stage for ectopic protein functioning is a novel therapeutic strategy. Joining the linear RNA head-to-tail covalently could be a state-of-the-art strategy for functioning longer. Here we enroll a cis-acting ligase ribozyme (RzL) to generate circular RNA (circRNA) in vitro for ectopic protein expression. The RNA circularization is confirmed by masking the 5' phosphate group, resisting exonuclease RNase R digestion, failing for further tailing, and sequencing the RT-PCR products of the joined region. Interestingly, one internal ribosome entry site (IRES) renders circRNA translation competent, but two IRES in cis, not trans, hamper the translation. The circRNA with highly potent in translation is conferred for antiviral functioning. Accompanying specific guided RNA, a circRNA expressing ribonuclease Cas13 shows excellent potential against the corresponding RNA virus, further extending circRNA functioning in its growing list of applications.

The Latency of Auditory Event-Related Potential P300 Prolonged in School-Age Students with Unilateral Hearing Loss in a Mandarin Learning Environment.

Our study investigated the differences in speech performance and neurophysiological response in groups of school-age children with unilateral hearing loss (UHL) who were otherwise typically developing (TD). We recruited a total of 16 primary school-age children for our study (UHL = 9/TD = 7), who were screened by doctors at Shin Kong Wu-Ho-Su Memorial Hospital. We used the Peabody Picture Vocabulary Test-Revised (PPVT-R) to test word comprehension, and the PPVT-R percentile rank (PR) value was proportional to the auditory memory score (by The Children's Oral Comprehension Test) in both groups. Later, we assessed the latency and amplitude of auditory ERP P300 and found that the latency of auditory ERP P300 in the UHL group was prolonged compared with that in the TD group. Although students with UHL have typical hearing in one ear, based on our results, long-term UHL might be the cause of atypical organization of brain areas responsible for auditory processing or even visual perceptions attributed to speech delay and learning difficulties.

Locoregional treatment improves overall survival for liver cancer during second-line regorafenib or immune checkpoint inhibitor.

For advanced hepatocellular carcinoma (HCC), the best second-line treatment after first-line treatment with sorafenib is unclear. This study aimed to compared the efficacy of second-line regorafenib (a tyrosine kinase inhibitor) and immune checkpoint inhibitors (ICIs) in patients with advanced HCC after sorafenib therapy. This retrospective study included 89 patients with HCC treated with sorafenib, and then regorafenib (n = 58) or an ICI (n = 31). Treatment response, overall survival (OS) and progression-free survival (PFS) of the 2 groups were compared, and factors associated with post-treatment mortality or disease progression were evaluated. During follow-up period, compared to regorafenib, treatment with an ICI results in a slight increase in a 20% decrease of AFP (35.7% vs. 31.8%), complete response rate (6.5% vs. 0%), objective response rate (16.1% vs. 6.9%), median overall survival (13.3 vs. 5 months), and median PFS (3.0 vs. 2.6 months). Combined locoregional treatment (LRT) (hazard ratio [HR] = 0.40, 95% confidence interval [CI]: 0.15-0.99) during second-line treatment was associated with a decreased risk of post-treatment mortality. After propensity scoring matching, combined LRT during second-line treatment had longer post-treatment OS than patients without combined LRT. A 20% decrease of AFP (HR = 0.54, 95% CI: 0.31-0.94) was associated with a decreased risk of post-treatment disease progression. In conclusions, second-line treatment with regorafenib or ICI prolongs OS in patients with advanced HCC treated with sorafenib. Combined LRT during second-line treatment is associated with decreased post-treatment mortality. A 20% decrease of AFP level may be predictive of a lower rate of disease progression.

Interfacing centrifugal microfluidics with linear-oriented 8-tube strips and multichannel pipettes for increased throughput of digital assays.

We present a centrifugal microfluidic cartridge for the eight-fold parallel generation of monodisperse water-in-oil droplets using standard laboratory equipment. The key element is interfacing centrifugal microfluidics with its design based on polar coordinates to the linear structures of standard high-throughput laboratory automation. Centrifugal step emulsification is used to simultaneously generate droplets from eight samples directly into standard 200 µl PCR 8-tube strips. To ensure minimal manual liquid handling, the design of the inlets allows the user to load the samples and the oil via a standard multichannel pipette. Simulation-based design of the cartridge ensures that the performance is consistent in each droplet generation unit despite the varying radial positions that originate from the interface to the linear oriented PCR 8-tube strip and from the integration of linear oriented inlet holes for the multichannel pipettes. Within 10 minutes, sample volumes of 50 µl per droplet generation unit are emulsified at a fixed rotation speed of 960 rpm into 1.47 × 105 monodisperse droplets with a mean diameter of 86 µm. The overall coefficient of variation (CV) of the droplet diameter was below 4%. Feasibility is demonstrated by an exemplary digital droplet polymerase chain reaction (ddPCR) assay which showed high linearity (R2 ≥ 0.999) across all of the eight tubes of the strip.

Zika virus cleaves GSDMD to disseminate prognosticable and controllable oncolysis in a human glioblastoma cell model.

Glioblastoma (GBM) is the most common aggressive malignant brain cancer and is chemo- and radioresistant, with poor therapeutic outcomes. The "double-edged sword" of virus-induced cell death could be a potential solution if the oncolytic virus specifically kills cancer cells but spares normal ones. Zika virus (ZIKV) has been defined as a prospective oncolytic virus by selectively targeting GBM cells, but unclear understanding of how ZIKV kills GBM and the consequences hinders its application. Here, we found that the cellular gasdermin D (GSDMD) is required for the efficient death of a human GBM cell line caused by ZIKV infection. The ZIKV protease specifically cleaves human GSDMD to activate caspase-independent pyroptosis, harming both viral protease-harboring and naive neighboring cells. Analyzing human GSDMD variants showed that most people were susceptible to ZIKV-induced cytotoxicity, except for those with variants that resisted ZIKV cleavage or were defective in oligomerizing the N terminus GSDMD cleavage product. Consistently, ZIKV-induced secretion of the pro-inflammatory cytokine interleukin-1ß and cytolytic activity were both stopped by a small-molecule inhibitor targeting GSDMD oligomerization. Thus, potential ZIKV oncolytic therapy for GBM would depend on the patient's GSDMD genetic background and could be abolished by GSDMD inhibitors if required.

Molecule transfer into mammalian cells by single sub-nanosecond laser pulses.

A rapid, precise, and viability-retaining method for cytoplasmic molecule delivery is highly desired for cell engineering. Routine methods suffer from low throughput, lack of selectivity, requirement of helper compounds, predominant endosomal delivery, and/or are restricted to specific molecule classes. Photonic cell manipulation bears the potential to overcome these drawbacks. Here we investigated mammalian cell manipulation by single sub-nanosecond laser pulses. Axial beam waist positioning close to a cell monolayer induced culture vessel damage and zones of cell ablation. Cells at margins of ablation zones exhibited uptake of membrane-impermeant fluorophores and GFP expression plasmids. Increasing Rayleigh-length and beam waist diameter reduced the sensitivity to axial defocusing and resulted in robust molecule transfer. Serial application of single pulses focused over a moving cell monolayer yielded quantitative molecule transfer to cells at rates up to 40%. Our results could be basic to spatially and temporally controlled single laser pulse-mediated marker-free high throughput cell manipulation.

Bifunctional Monolayer WSe2/Graphene Self-Stitching Heterojunction Microreactors for Efficient Overall Water Splitting in Neutral Medium.

Developing efficient bifunctional electrocatalysts in neutral media to avoid the deterioration of electrodes or catalysts under harsh environments has become the ultimate goal in electrochemical water splitting. This work demonstrates the fabrication of an on-chip bifunctional two-dimensional (2D) monolayer (ML) WSe2/graphene heterojunction microreactor for efficient overall water splitting in a neutral medium (pH = 7). Through the synergistic atomic growth of the metallic Cr dopant and graphene stitching contact on the 2D ML WSe2, the bifunctional WSe2/graphene heterojunction microreactor consisting of a full-cell configuration demonstrates excellent performance for overall water splitting in a neutral medium. Atomic doping of metallic Cr atoms onto the 2D ML WSe2 effectively facilitates the charge transfer at the solid-liquid interface. In addition, the direct growth of the self-stitching graphene contact with the 2D WSe2 catalyst largely reduces the contact resistance of the microreactor and further improves the overall water splitting efficiency. A significant reduction of the overpotential of nearly 1000 mV at 10 mA cm-2 at the Cr-doped WSe2/graphene heterojunction microreactor compared to the ML pristine WSe2 counterpart is achieved. The bifunctional WSe2/graphene self-stitching heterojunction microreactor is an ideal platform to investigate the fundamental mechanism of emerging bifunctional 2D catalysts for overall water splitting in a neutral medium.

A substructure-based screening approach to uncover N-nitrosamines in drug substances.

Drug substances are at risk of contamination with N-nitrosamines (NAs), well-known carcinogenic agents, during synthesis processes and/or long-term storage. Therefore, in this study, we developed an efficient data-based screening approach to systemically assess marketed products and investigated its scalability for benefiting both regulatory agencies and pharmaceutical industries. A substructure-based screening method employing DataWarrior, an open-source software, was established to evaluate the risks of NA impurities in drug substances. Eight NA substructures containing susceptible amino sources for N-nitrosation have been identified as screening targets: dimethylamine (DMA), diethylamine, isopropylethylamine, diisopropylamine, N-methyl-2-pyrrolidone, dibutylamine, methylphenylamine, and tetrazoles. Our method detected 192 drug substances with a theoretical possibility of NA impurity, 141 of which had not been reported previously. In addition, the DMA moiety was significantly dominant among the eight NA substructures. The results were validated using data from the literature, and a high detection sensitivity of 0.944 was demonstrated. Furthermore, our approach has the advantage of scalability, owing to which 31 additional drugs with suspected NA-contaminated substructures were identified using the substructures of 1-methyl-4-piperazine in rifampin and 1-cyclopentyl-4-piperazine in rifapentine. In conclusion, the reported substructure-based approach provides an effective and scalable method for the screening and investigation of NA impurities in various pharmaceuticals and might be used as an ancillary technique in the field of pharmaceutical quality control for risk assessments of potential NA impurities.

Microfluidic One-Pot Digital Droplet FISH Using LNA/DNA Molecular Beacons for Bacteria Detection and Absolute Quantification.

We demonstrate detection and quantification of bacterial load with a novel microfluidic one-pot wash-free fluorescence in situ hybridization (FISH) assay in droplets. The method offers minimal manual workload by only requiring mixing of the sample with reagents and loading it into a microfluidic cartridge. By centrifugal microfluidic step emulsification, our method partitioned the sample into 210 pL (73 µm in diameter) droplets for bacterial encapsulation followed by in situ permeabilization, hybridization, and signal detection. Employing locked nucleic acid (LNA)/DNA molecular beacons (LNA/DNA MBs) and NaCl-urea based hybridization buffer, the assay was characterized with Escherichia coli, Klebsiella pneumonia, and Proteus mirabilis. The assay performed with single-cell sensitivity, a 4-log dynamic range from a lower limit of quantification (LLOQ) at ~3 × 103 bacteria/mL to an upper limit of quantification (ULOQ) at ~3 × 107 bacteria/mL, anda linearity R2 = 0.976. The total time-to-results for detection and quantification was around 1.5 hours.

Small Structural Proteins E and M Render the SARS-CoV-2 Pseudovirus More Infectious and Reveal the Phenotype of Natural Viral Variants.

The SARS-CoV-2 pseudovirus is a commonly used strategy that mimics certain biological functions of the authentic virus by relying on biological legitimacy at the molecular level. Despite the fact that spike (S), envelope (E), and membrane (M) proteins together wrap up the SARS-CoV-2 virion, most of the reported pseudotype viruses consist of only the S protein. Here, we report that the presence of E and M increased the virion infectivity by promoting the S protein priming. The S, E, and M (SEM)-coated pseudovirion is spherical, containing crown-like spikes on the surface. Both S and SEM pseudoviruses packaged the same amounts of viral RNA, but the SEM virus bound more efficiently to cells stably expressing the viral receptor human angiotensin-converting enzyme II (hACE2) and became more infectious. Using this SEM pseudovirus, we examined the infectivity and antigenic properties of the natural SARS-CoV-2 variants. We showed that some variants have higher infectivity than the original virus and that some render the neutralizing plasma with lower potency. These studies thus revealed possible mechanisms of the dissemination advantage of these variants. Hence, the SEM pseudovirion provides a useful tool to evaluate the viral infectivity and capability of convalescent sera in neutralizing specific SARS-CoV-2 S dominant variants.

Evaluation of inhibitors of intestinal UDP-glucuronosyltransferases 1A8 and 1A10 using raloxifene as a substrate in Caco-2 cells: Studies with four flavonoids of Scutellaria baicalensis.

UDP glucuronosyltransferases (UGTs) of the gastrointestinal tract play a crucial role in protection against the toxic effects of xenobiotics in the environment. UGTs such as UGT1A8 and UGT1A10 are predominantly expressed in gastrointestinal tissues. In this study, we examined the phase II metabolism of raloxifene in differentiated Caco-2 monolayers by inducing UGT1A8 and UGT1A10 expression in these cells. The present study evaluated the following four flavonoids of Scutellaria baicalensis as model herbal compounds: scutellarein, salvigenin, baicalein, and wogonin. All test compounds, endpoint substrates, and their metabolites were quantified using liquid chromatography and high-resolution mass spectrometry. The transepithelial electrical resistance values for the individual compounds were comparable regardless of whether they were measured individually. Salvigenin significantly inhibited UGT1A8 and UGT1A10 activities in a concentration-dependent manner. All individual compounds except scutellarein inhibited UGT1A8 and UGT1A10 activity at a concentration of 100 µM. In addition, all individual flavonoids at 100 µM, except wogonin, significantly increased the amount of raloxifene in the basolateral chambers. The positive control, canagliflozin, significantly inhibited both UGT1A8 and UGT1A10 activities. These findings suggest that the Caco-2 assay can be utilized for identifying UGT1A8 and UGT1A10 inhibitors and indicate the potential of salvigenin for enhancing the pharmacological effects of UGT substrate drugs.

DNA-induced 2'3'-cGAMP enhances haplotype-specific human STING cleavage by dengue protease.

The cytosolic DNA sensor cGMP-AMP synthase (cGAS) synthesizes the noncanonical cyclic dinucleotide 2'3'-cGAMP to activate the adaptor protein stimulator of IFN genes (STING), thus awakening host immunity in response to DNA pathogen infection. However, dengue virus (DENV), an RNA virus without a DNA stage in its life cycle, also manipulates cGAS-STING-mediated innate immunity by proteolytic degradation of STING. Here, we found that the sensitivity of STING to DENV protease varied with different human STING haplotypes. Exogenous DNA further enhanced DENV protease's ability to interact and cleave protease-sensitive STING. DNA-enhanced STING cleavage was reduced in cGAS-knockdown cells and triggered by the cGAS product 2'3'-cGAMP. The source of DNA may not be endogenous mitochondrial DNA but rather exogenous reactivated viral DNA. Cells producing 2'3'-cGAMP by overexpressing cGAS or with DNA virus reactivation enhanced STING cleavage in neighboring cells harboring DENV protease. DENV infection reduced host innate immunity in cells with the protease-sensitive STING haplotype, whose homozygote genotype frequency was found significantly reduced in Taiwanese people with dengue fever. Therefore, the human STING genetic background and DNA pathogen coinfection may be the missing links contributing to DENV pathogenesis.

A Quinone-Based Electrode for High-Performance Rechargeable Aluminum-Ion Batteries with a Low-Cost AlCl3/Urea Ionic Liquid Electrolyte.

Intensive energy demand urges state-of-the-art rechargeable batteries. Rechargeable aluminum-ion batteries (AIBs) are promising candidates with suitable cathode materials. Owing to high abundance of carbon, hydrogen, and oxygen and rich chemistry of organics (structural diversity and flexibility), small organic molecules are good choices as the electrode materials for AIB. Herein, a series of small-molecule quinone derivatives (SMQD) as cathode materials for AIB were investigated. Nonetheless, dissolution of small organic molecules into liquid electrolytes remains a fundamental challenge. To nullify the dissolution problem effectively, 1,4-benzoquinone was integrated with four bulky phthalimide groups to form 2,3,5,6-tetraphthalimido-1,4-benzoquinone (TPB) as the cathode materials and assembled to be the AI/TPB cell. As a result, the Al/TPB cell delivered capacity as high as 175 mA h/g over 250 cycles in the urea electrolyte system. Theoretical studies have also been carried out to reveal and understand the storage mechanism of the TPB electrode.

Real-Time Observation of Anion Reaction in High Performance Al Ion Batteries.

Recently, aluminum ion batteries (AIBs) have attracted great attention across the globe by virtue of their massive gravimetric and volumetric capacities in addition to their high abundance. Though carbon derivatives are excellent cathodes for AIBs, there is much room for further development. In this study, flexuous graphite (FG) was synthesized by a simple thermal shock treatment, and for the first time, an Al/FG battery was applied as a cathode for AIBs to reveal the real-time intercalation of AlCl4- into FG with high flexibility by using in-situ scanning electron microscope (SEM) measurements exclusively. Similarly, in-situ X-ray diffraction (XRD) and in-situ Raman techniques have been used to understand the anomalous electrochemical behavior of FG. It was found that FG adopts a unique integrated intercalation-adsorption mechanism where it follows an intercalation mechanism potential above 1.5 V and an adsorption mechanism potential below 1.5 V. This unique integrated intercalation-adsorption mechanism allows FG to exhibit superior properties, like high capacity (≥140 mAh/g), remarkable long-term stability (over 8000 cycles), excellent rate retention (93 mAh/g at 7.5 A/g), and extremely rapid charging and slow discharging.

Gravity-driven microfluidic assay for digital enumeration of bacteria and for antibiotic susceptibility testing.

The alarming dynamics of antibiotic-resistant infections calls for the development of rapid and point-of-care (POC) antibiotic susceptibility testing (AST) methods. Here, we demonstrated the first completely stand-alone microfluidic system that allowed the execution of digital enumeration of bacteria and digital antibiograms without any specialized microfluidic instrumentation. A four-chamber gravity-driven step emulsification device generated ∼2000 monodisperse 2 nanoliter droplets with a coefficient of variation of 8.9% of volumes for 95% of droplets within less than 10 minutes. The manual workload required for droplet generation was limited to the sample preparation, the deposition into the sample inlet of the chip and subsequent orientation of the chip vertically without an additional pumping system. The use of shallow chambers imposing a 2D droplet arrangement provided superior stability of the droplets against coalescence and minimized the leakage of the reporter viability dye between adjacent droplets during long-term culture. By using resazurin as an indicator of the growth of bacteria, we were also able to reduce the assay time to ∼5 hours compared to 20 hours using the standard culture-based test.

A novel finding of nalbuphine-6-glucuronide, an active opiate metabolite, possessing potent antinociceptive effects: Synthesis and biological evaluation.

Nalbuphine, a partial agonist/antagonist opioid analgesic, is structurally related to morphine. It is equipotent to morphine and has no serious side effects. In the past few decades, studies focusing on morphine metabolism have indicated that one of its sugar-conjugated metabolites, morphine-6-glucuronide, exerts a higher analgesic effect than its parent drug. Considering that nalbuphine is a morphine analog that follows a similar metabolic scheme, nalbuphine glucuronides were synthesized in this study and their potential analgesic effects were assessed. Nalbuphine-3-glucuronide (N3G) and nalbuphine-6-glucuronide (N6G) were synthesized based on Schmidt's glycosylation with OPiv protections on the glycosyl donor. In a pharmacodynamic study, paw pressure and cold-ethanol tail-flick tests were conducted in rats to evaluate the analgesic response after intracisternal and intraperitoneal administrations of nalbuphine, N3G, or N6G. The antinociceptive response was evaluated for each compound by calculating the area under the curve and the duration spent at greater than 50% maximum possible analgesia. In conclusion, intracisternal administration of N6G exhibited a stronger analgesic response than nalbuphine in the pain tests after both cold and mechanical stimuli, but N3G had no obvious effect. Similar to that of morphine, the glucuronide metabolite of nalbuphine at the 6-O-position exerted at least three-fold higher antinociceptive potency and five-fold longer analgesic duration than nalbuphine.

Clinicopathologic analysis of renal epithelioid angiomyolipoma: Consecutively excised 23 cases.

Renal epithelioid angiomyolipoma (eAML) is considered a malignant variant of angiomyolipoma (AML). From 2001 to 2016, a total of 570 patients were diagnosed with renal AML in Linko Chang Gung Memorial Hospital, Taiwan, including 23 cases of renal eAML. All 23 eAML cases were made up of at least 10% of epithelioid cells histologically. Three of these cases were found with multiple tumors. Two cases developed distant metastasis: one had mediastinal lymph nodes and bilateral lung metastasis; the other one had tumor recurrence over liver and retroperitoneum 1 year after radical nephrectomy. They were then divided into invasive (n = 5) and noninvasive (n = 18) groups according to their clinical behavior. The invasive group showed more severe nuclear atypia and higher rates in tumor necrosis. There was statistically no significance in relation to a patient's age, tumor size, and mitotic count between two groups. After conducting a series of studies, we suggest treating eAML with the guideline of renal cell carcinoma.

Clinical behavior and management of three types of renal angiomyolipomas.

OBJECTIVES: To analyze and present the demography, clinical behavior, especially the risk factors of tumor hemorrhage and management of sporadic angiomyolipoma (SAML), tuberous sclerosis complex associated angiomyolipoma (TSCAML) and epithelioid angiomyolipoma (EAML) in our institution. METHODS: A retrospective study of 587 patients who were diagnosed with renal angiomyolipoma in our institution between January 2000 and May 2015 was done. The AMLs were diagnosed by ultrasonography, CT, or MRI. EAML was confirmed by histopathology. Medical records and follow-up results were analyzed using the SPSS version 22 software. RESULTS: Out of 587 cases of renal AMLs, 87.4% were SAMLs, 8.7% were TSCAMLs and 3.9% were EAMLs. Most of the AML patients were asymptomatic. The most common presenting symptoms included flank pain and abdominal pain. The median tumor size of SAML, TSCAML, EAML were 4.7, 2.7, 10.5 cm respectively. Approximately half of SAMLs were conservatively treated, almost all TSCAMLs were treated conservatively, while all EAMLs were surgically treated. The median tumor size of hemorrhagic SAML cases was 8 cm versus non-hemorrhagic cases of 4.1 cm. The optimal cut-off point on the ROC curve for predicting SAML tumor hemorrhage was 7.35 cm. CONCLUSION: A larger tumor size, younger patient's age and higher BMI value correlated with a higher risk of tumor hemorrhage. For tumor sizes less than 7.35 cm, we recommend active surveillance or TAE for hemorrhage prevention. We also suggest that surgical management should be considered for patients with tumors larger than 7.35 cm, symptomatic and progressive AML, or suspicious EAML.

How Dengue Virus Circumvents Innate Immunity.

In the battle between a virus and its host, innate immunity serves as the first line of defense protecting the host against pathogens. The antiviral actions start with the recognition of pathogen-associated molecular patterns derived from the virus, then ultimately turning on particular transcription factors to generate antiviral interferons (IFNs) or proinflammatory cytokines via fine-tuned signaling cascades. With dengue virus (DENV) infection, its viral RNA is recognized by the host RNA sensors, mainly retinoic acid inducible gene-I (RIG-I)-like receptors (RLRs) and toll-like receptors. DENV infection also activates the cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING)-mediated DNA-sensing pathway despite the absence of a DNA stage in the DENV lifecycle. In the last decade, DENV has been considered a weak IFN-inducing pathogen with the evidence that DENV has evolved multiple strategies antagonizing the host IFN system. DENV passively escapes from innate immunity surveillance and also actively subverts the innate immune system at multiple steps. DENV targets both RNA-triggered RLR-mitochondrial antiviral signaling protein (RLR-MAVS) and DNA-triggered cGAS-STING signaling to reduce IFN production in infected cells. It also blocks IFN action by inhibiting IFN regulatory factor- and signal transducer and activator of transcription-mediated signaling. This review explores the current understanding of how DENV escapes the control of the innate immune system by modifying viral RNA and viral protein and by post-translational modification of cellular factors. The roles of the DNA-sensing pathway in DENV infection, and how mitochondrial dynamics participates in innate immunity are also discussed.

Effect of Different CH3NH3PbI3 Morphologies on Photovoltaic Properties of Perovskite Solar Cells.

In this study, the perovskite layers were prepared by two-step wet process with different CH3NH3I (MAI) concentrations. The cell structure was glass/FTO/TiO2-mesoporous/CH3NH3PbI3 (MAPbI3)/spiro-OMeTAD/Ag. The MAPbI3 perovskite films were prepared using high and low MAI concentrations in a two-step process. The perovskite films were optimized at different spin coating speed and different annealing temperatures to enhance the power conversion efficiency (PCE) of perovskite solar cells. The PCE of the resulting device based on the different perovskite morphologies was discussed. The PCE of the best cell was up to 17.42%, open circuit voltage of 0.97 V, short current density of 24.06 mA/cm2, and fill factor of 0.747.