Cellulose-Based Sensor Containing Phenanthroline for the Highly Selective and Rapid Detection of Fe²⁺ Ions with Naked Eye and Fluorescent Dual Modes

Iron ions play a vital role in many biological processes, and their concentrations are responsible for human health. Therefore, it is essential to detect the concentration of iron ions by a rapid, accurate, highly selective, and practical method. Herein, we have synthesized a cellulose-based fluorescent sensor (Phen-MDI-CA) for the highly selective and rapid detection of Fe²⁺ ions via chemically bonding 1,10-phenanthroline-5-amine (Phen) onto cellulose acetate (CA) using 4,4′-methylene diphenyl diisocyanate (MDI) as a cross-linker. Benefiting from the anchoring and diluting effect of a cellulose skeleton, the resultant Phen-MDI-CA displays excellent fluorescence properties in both solution and solid state. More interestingly, a cellulose-based polymer chain significantly improves the sensitivity of phenanthroline to Fe²⁺ ions. Upon meeting Fe²⁺ ions, a red, insoluble, and nonfluorescent Fe–(Phen-MDI-CA) complex appears immediately; thus, Phen-MDI-CA can work as a multimode chromogenic sensor for the highly selective, sensitive, and rapid detection of Fe²⁺ ions. In the instrument-free visual mode, the detection limit for Fe²⁺ ions is 50 ppb, and in fluorescence mode, the detection limit is 2.6 ppb. To our knowledge, this is the first time that such a low detection limit for Fe²⁺ ions in aqueous media has been observed by the naked eye. In addition, Phen-MDI-CA has good solubility and processability in common organic solvents, which facilitates its use in different material forms, e.g., printing ink, coating, and film. Therefore, the Fe²⁺-responsive and chromogenic Phen-MDI-CA exhibits a huge potential in the detection and extraction of Fe²⁺ ions

Demographic Distribution (n = 475)

<p>Demographic Distribution (n = 475)</p

Characterization of Illicit Drugs by Surface-Enhanced Raman Spectroscopy (SERS) and Principal Component Analysis (PCA)

Addictive, illicit drugs pose a high threat of relapse. The deaths related to illicit drugs have substantially increased in the last decade. Globally, the illicit drug trade poses a significant challenge to public health and law enforcement. It is essential to utilize advanced analytical methodologies that can characterize illegal substances precisely to monitor these drugs. Surfaced-enhanced Raman spectroscopy (SERS) has become a valuable tool, providing distinct capabilities for analyzing illegal substances. Surface enhancement enables far more sensitive detection and identification of illicit drugs by suppressing the fluorescence and enhancing the Raman signals. In this regard, a simple method with limited sample processing has been established to characterize illicit drugs that include methamphetamine (MAMP) (ice), bhang, marijuana (cannabis), opium, and diacetylmorphine (heroin). Moreover, principal component analysis (PCA) was employed for the identification of the characteristic SERS spectral features of these drugs. This article examines the potential application of SERS in the characterization of illicit substances, focusing on its ability to contribute significantly to law enforcement and forensic investigation.</p

PRISMA flow diagram for review of manuscripts.

<p>PRISMA flow diagram for review of manuscripts.</p

Emerging thematic areas from breast and cervical cancer reviews in low- and middle-income countries (LMICs).

<p><b>Note</b>: “Reviewed” indicates that the publication reviewed studies that pertained to this theme. “Recommended” indicates that the publication presented recommendations on the given subject.</p><p>^a Include reviews that assess technical or behavioral interventions</p><p>^b Includes reviews that discuss policy, regulation, financing, public education, needs, constraints, barriers, and partnerships.</p><p>^c Includes reviews that discuss considerations of organizational improvement would have commented on topics such as implementation, quality improvement, quality assurance, performance management, guidelines, and systems strengthening.</p><p>^d Includes reviews that discuss training, continuing education, and peer learning.</p><p>^e includes reviews that discuss considerations of community empowerment, participation, information and education, social marketing, community-managed services, public health approaches, and community mobilization</p><p>Emerging thematic areas from breast and cervical cancer reviews in low- and middle-income countries (LMICs).</p

Descriptive summary of breast and cervical cancer reviews in low- and middle-income countries (LMICs).

<p>Descriptive summary of breast and cervical cancer reviews in low- and middle-income countries (LMICs).</p

Reviews of cervical cancer in low- and middle-income countries (LMICs).

<p>^a P = prevention, De = detection, Di = Diagnosis, T = Treatment, S = survivorship, All = all aspects</p><p>Reviews of cervical cancer in low- and middle-income countries (LMICs).</p

Reviews of breast cancer in low- and middle-income countries (LMICs).

<p>^a P = prevention, De = detection, Di = Diagnosis, T = Treatment, S = survivorship, All = all aspects</p><p>Reviews of breast cancer in low- and middle-income countries (LMICs).</p