Permanent Hair Dyes Research Articles

Alternative chromogenic substrates for horseradish peroxidase-enhanced lateral flow immunoassays provide higher sensitivity at lower cost

Lateral flow immunoassays (LFIAs or LFAs) have become indispensable in point-of-care medical diagnostics, but improving their sensitivity remains a critical challenge. In this work, we present a strategy to enhance LFA sensitivity by introducing novel oxidative coupling-based chromogenic substrates for horseradish peroxidase (HRP)-based enzymatic sensitivity enhancement. Motivated by the requirement for more sensitive and cost-effective LFAs, we developed substrates inspired by the chemistry of permanent oxidative hair dyes. These substrates consist of two components: a primary intermediate and a coupler that undergo an oxidative coupling reaction in the presence of H2O2, catalyzed by HRP, to generate an intensely colored dye. LFAs employing these substrates outperformed conventional substrates (3,3′-diaminobenzidine (DAB) and 3,3′,5,5′-tetramethylbenzidine (TMB)) and achieved an unprecedented sub-ng/mL limit of detection (LoD) for human IgG as a model analyte. LFAs employing these novel substrates could detect human IgG at 0.16 ng/mL (1.07 pM), significantly surpassing reported sensitivities in the literature. These LFAs also exhibit over 40 times improved sensitivity compared to standard gold nanoparticle-based LFAs. Moreover, these substrates are about 10,000X more cost-effective than their conventional counterparts, thus making them a compelling choice for point-of-care diagnostics in low-resource settings.

Healthy lifestyle choices: new insights into vitiligo management.

The treatment of vitiligo is complex, and providing guidance based on lifestyle habits is a good option that has not been summarized or analyzed. To elucidate the relationship between vitiligo and lifestyle factors. Four databases (PubMed, Embase, Cochrane, and China National Knowledge Internet) were searched for articles published between 1980 and December 2022. Keywords such as smoking, drinking, exercise, diet, and sleep were used. Based on the search strategy, 875 relevant studies were retrieved, and 73 were included in this study, of which 41 studies with 8,542 patients with vitiligo were included in the meta-analysis. Vitamin C [mean difference (MD), -0.342; 95% confidence interval (CI), -1.090-0.407; p >0.05), folic acid (MD, -1.463; 95% CI, -7.133-4.208; p >0.05), and selenium (MD, 0.350; 95% CI, -0.687-1.387; p >0.05) levels did not differ between the groups. Vitamin E (MD, -1.408; 95% CI, -2.611--0.206; p <0.05), vitamin B12 (MD, -0.951; 95% CI, -1.672--0.275; p <0.05), copper (MD, -0.719; 95% CI, -1.185--0.252, p <0.005), and zinc (MD, -0.642; 95% CI, -0.731--0.554; p <0.001) levels were lower in the vitiligo group than in the control group. The serum iron level of the vitiligo group was significantly higher than that of the control group (MD, 1.181; 95% CI, 0.390-1.972; p <0.005). Finally, more participants in the vitiligo group smoked and drank alcohol than those in the control group. Most studies are from Eastern countries; thus, extrapolating these results to Western populations is questionable. The significant heterogeneity may be attributed to the different stages, types, duration, center settings, population registries, etc., which seriously impair the validity of the results. Patients with vitiligo should reduce smoking and alcohol consumption and take appropriate vitamin E, B12, copper, and zinc supplements. However, vitamin C, vitamin D, selenium, iron, and folic acid supplements are unnecessary. Moreover, they should consider sun protection and avoid permanent hair dye use. Patients with vitiligo may experience sleep disturbances and sexual dysfunction, and these patients should seek help from a specialist if necessary. https://www.crd.york.ac.uk/prospero/#recordDetails, identifier CRD42023480757.

Hepatocellular carcinoma antibodies preferably identify nitro-oxidative-DNA lesions induced by 4-Chloro-orthophenylenediamine and DEANO

The widespread use of oxidative hair colouring cosmetics threatens public health. Phenylenediamine derivatives serve as the main pigment in permanent hair colours. They interact with biological macromolecules, altering their functional and structural physiology. The study aimed to investigate the effect of a typical synthetic hair dye pigment, 4-Chloro-orthophenylenediamine (4-Cl-OPD), under a nitrating environment of DEANO on the calf thymus DNA molecule. The results showed single-stranded regions, base/sugar-phosphate backbone alterations, molecular changes, and nitro-oxidative lesions. These modifications are referred to as neo-epitopes on the DNA molecule. IgGs from cancer patients with a history of permanent hair dye use were screened for the recognition of neo-epitopes on DNA molecules. Hepatocellular carcinoma IgG showed the highest binding with 56% inhibition in the competition ELISA. The immune complex formation was observed through electrophoretic mobility shift assay. In conclusion, synthetic hair dye users are likely to present with heightened immunological triggers under elevated nitric oxide levels. The study reports chronic hair dye exposure as one of the factors responsible for altering the intricacies of the DNA’s microarchitectural structure and inducing neo-epitopes on the molecule. The physiological status of NO may define the susceptibility towards 4-Cl-OPD and humoral response in hair dye users. Persistent nitro-oxidative stress due to 4-Cl-OPD and NO may induce a heightened immune response against neoepitopes in the nitro-oxidatively modified DNA. Therefore, chronic hair dye exposure may be identified as a risk to human health. These findings may contribute to a better understanding and reinforcement of hair dye as one of the modifiable risk factors responsible for the pro-inflammatory carcinogenic environment.

Acetyl zingerone methyl ether protects hair against oxidative damage incurred during and after treatment with permanent dyes and helps extend longevity of newly developed hair colour.

Use of permanent hair dyes causes unintended oxidative damage during the short time frame of the dyeing process that leads to perceivable changes in the feel, manageability and appearance of hair. Moreover, after hair has been dyed, regular exposure to the sun as a key environmental stressor continues to stimulate additional oxidative damage and to induce newly developed hair colours to fade prematurely or undergo changes in colour quality. To document the utility of acetyl zingerone methyl ether (MAZ) as a newly designed haircare ingredient to afford extra protection against oxidative damage and safeguard the integrity of hair colour. We demonstrate that MAZ is compatible chemically with the high alkaline conditions required for the colouring process and from theoretical calculations preferentially binds Fe and Cu ions relative to Ca or Zn ions. In model Fenton reactions MAZ effectively chelated active redox metals (Fe and Cu ions) in the presence of excess Ca+2 ions to inhibit the production of hydroxyl radicals, and in separate studies, MAZ neutralized singlet oxygen with greater efficiency than α-tocopherol by a factor of 2.5. When mixed into permanent dyes prior to hair tress application, MAZ significantly reduced combing forces, and SEM images led to substantial reductions in visual signs of surface damage. In a 28-day clinical study, relative to controls, mixing MAZ into hair dyes prior to application interfered neither with colour development nor with ability to cover grey hair and led to significant improvements in perceived attributes associated with hair's condition immediately following the dyeing process. Over a 28-day maintenance phase, especially between Day 14 and Day 28, continued use of shampoo and conditioner containing MAZ significantly preserved gloss measurements and hair colour in terms of longevity and colour quality as remaining desired and fresh compared to use of control shampoo and conditioner. This work establishes MAZ as a next-generation hair care ingredient for use in permanent dyes to attenuate oxidative damage and in shampoos and conditioners to promote longevity of hair colour and to maintain overall health and appearance of hair on a daily basis.

Hair Dye and Relaxer Use among Cisgender Women in Embu and Nakuru Counties, Kenya: Associations with Perceived Risk of Breast Cancer and Other Health Effects.

Despite widespread use of hair products globally, little is known about the prevalence and patterns of use in populations outside the United States. As some hair products contain endocrine-disrupting chemicals (EDCs) and EDCs have been linked to breast cancer, which is increasing globally, in this study, we addressed key knowledge gaps about hair product use and practices, and perceptions of use among women in two counties in Kenya. Using community-engaged approaches in Embu and Nakuru, Kenya, we recruited women aged 15-50 years to complete a questionnaire that ascertained hair product use in the last 7-14 days, ever using hair dyes and chemical relaxers, and participants' perceptions or harm around hair product use. In multivariable-adjusted regression models, we evaluated associations between participants' sociodemographic characteristics and perceptions of hair product use in relation to if they have ever used hair dyes and relaxers. In our sample of 746 women (mean age, 30.4 ± 8.1 years), approximately one-third of participants reported ever using permanent and/or semi-permanent hair dyes, with approximately one-fifth reporting current use. Almost 60% reported ever using chemical relaxers, with a little over one-third reporting current use. Increasing age and having an occupation in the sales and service industry were statistically significant predictors of hair dye use (OR 1.04, 95% CI: 1.02-1.06 and OR 2.05, 95% CI: 1.38-3.03, respectively) and relaxer use (OR 1.03, 95% CI: 1.01-1.06 and OR 1.93, 95% CI: 1.30-2.87). On average, participants reported moderate-to-high levels of concern about exposures and general health effects from using hair products, and relatively high levels of perceived risk of breast cancer related to hair product use. However, in contrast to our hypotheses, we observed mixed evidence regarding whether higher levels of perceived risk were associated with lower odds of ever using hair dyes and relaxers. These findings add new knowledge to the extant literature on hair product use among women in Kenya, where breast cancer incidence rates are increasing. Improving the understanding of patterns of use of specific products and their chemical ingredients-which may be hormone disruptors or carcinogens-and exploring the role of environmental health literacy are critical for developing interventions to reduce potentially harmful exposures found in these products.

Development and Evaluation of Polyherbal Hair Dye Formulation

Background and objectives: Hair care products including hair dye play an important role in the maintenance and enhancement of appearance and overall wellbeing of the hair. Most of the hair dye available in the market contains harmful chemicals that may cause allergic reactions or irritation of the scalp. The objective of this study focuses on the formulation and evaluation of hair dye as creams and gels with different shades by using herbs. Methodology: The collected plants were authenticated, and shade dried. Then, extractions were done using water, ethanol, and methanol. Preliminary testing was conducted to obtain burgundy, brown and black by manipulating the ratios. Later, almond oil, coconut oil, beeswax and Carbopol-934 gel were added to ease the penetration. Finally, accelerated stability studies were done to check the physical and microbial stability of the product. Results: Eight different shades of hair dye were formulated in gel and cream form. Among them gel formulation F5 and F6 as well as the cream formulations F1, F2, F3, F4, F7 and F8 demonstrated good staining and better colour intensity. The accelerated stability studies of F1 to F8 revealed that there is no change in the physical evaluation and no evidence of microbial contamination. Conclusion: The output of this research is suitable for all races and age group because it is not a permanent hair dye that might have a restriction for some groups of races. As such, this hair dye is fully formulated with natural sources by considering in the reduction of severe side effects to the consumers.

Quantification of p-Phenylenediamine in Hair Dyes and Health Risk Implications in the UAE: Describing Discordances Between Regulations and Real-Life Practices.

p-Phenylenediamine (PPD) has been used over the past five decadesas a primary precursor in the production of oxidative hair dyes. Numerous health dangers are associated with the short- and long-term use of PPD, raising concerns about its safety. For instance, mounting data suggests that PPD is linked to dermatitis and allergy cases. To quantify the PPD content in hair dyes by measuring the PPD concentration after mixing the ingredients of commercial hair dyes. A total of 290 permanent hair dyes were tested. RP-HPLC-DAD analysis was performed to determine and quantify the PPD content. The estimated mean of the PPD limit was 0.89 (95% CI [0.81-0.96]). Of the 290 tested hair dyes, 7.2% (n = 21) exceeded the recommended PPD concentration after mixing. Significantly more hair dyes manufactured in India and China had a PPD content exceeding 2% after mixing compared to dyes from other regions (P = 0.001). Moreover, hair dyes manufactured in India and the UAE were more likely to have incomplete descriptions of the conditions of use and warnings on the label (P = 0.002). The effectiveness of the current regulations relevant to these products should be reevaluated. Moreover, through the use of good manufacturing procedures (GMPs), research, and the reporting of adverse reactions, hair dyes should be subjected to better control and monitoring in terms oftheir safety and quality.

Small Molecule Para-Phenylenediamine Analogues with Enhanced Oxidation Potential as Viable Permanent Hair Dyes

Small Molecule Para-Phenylenediamine Analogues with Enhanced Oxidation Potential as Viable Permanent Hair Dyes

A real-world data analysis on the usage of paraphenylenediamine and ammonia free hair dye

Background: Dyeing of hair for various reasons is a common practice across a broad age group. Most hair dyes available in the market contain para-phenylenediamine (PPD) and/or ammonia, which are proven skin and scalp irritants. A quest for better tolerable hair dyes has led to emergence of toluene-2, 5-diamine sulfate (TDS) and monoethanolamine (MEA), as a substitute to PPD and ammonia, respectively. Methods: This retrospective study was conducted on 35 participants from four centers across India to evaluate the efficacy, and tolerance of ammonia-free and PPD-free permanent hair dye. Results: A PPD-free and ammonia-free cream-based hair dye showed promising results. The color uptake following 35 minutes of application was 100% in 54.2% of the participants. The color retention was more than 95% in 74.3% participants after 8-10 shampoo washes. The adverse effects were noted to be markedly less with only a few cases experiencing itching. The participants' feedback obtained showed a conclusively high satisfaction rate. The Physicians' assessment of efficacy and safety recorded favorable scores. Conclusions: A TDS and MEA based cream hair color can be an effective and safe alternative to PPD and ammonia-based hair dye.

Dermal exposure and hair dye: Assessing potential bladder cancer risk from permanent hair dye

Hair dye products include a range of chemicals, depending on the type and color. A common primary intermediate compound used to achieve the permanent effect of hair dye is para-phenylenediamine (PPD). 4-aminobiphenyl (4-ABP) has reportedly been found as a trace contaminant (presumably from the para-phenylenediamine [PPD] ingredient) in consumer permanent hair dye. While several regulatory agencies have designated 4-ABP as a human bladder carcinogen based on evidence in humans and experimental animals, only the Office of Environmental Health Hazard Assessment (OEHHA) have established a cancer risk value for 4-ABP of 0.03 μg/day based on liver tumors developed in mice. A hypothetical dermal risk assessment was performed to estimate the bladder cancer risk associated with exposure to 4-ABP from personal use of permanent hair dye potentially containing incidental 4-ABP. Previously published laboratory analyses characterizing 4-ABP concentrations in consumer hair dyes indicate the concentrations can range from below the limit of detection to 8120 ppb. Precautionary estimates of human scalp surface area, maximum skin adherence, hair dye retention factor, and percent dermal absorption were used to estimate the daily systemic exposure doses (SEDs) from dermal application of hair dye. The estimated SEDs ranged from 0.05 to 3000 pg/day. A margin of safety (MOS) was calculated as the ratio of the NSRL to the SED and ranged from 10 to 570,000. The results of this study suggest that there is no indication of increased risk of bladder cancer in humans from exposure to 4-ABP in consumer hair dye, especially as it is extremely unlikely that a consumer would use permanent hair dye on a daily basis (as this assessment models).

THE CHEMISTRY MECHANISM OF HAIR DYES

One of the oldest and most well-known cosmetics, hair color has been used by numerous ancient cultures throughout history on both men and women. It involves treating hair with various chemical compounds for changing hair color. According to how long they remain in the hair, these products are primarily divided into two categories: temporary and permanent. This classification is consistent with the types of active substances used in the dyeing process as well as the dyeing method itself, which are referred to as non-oxidative and oxidative hair dye products, respectively. Permanent hair dyes often consist of active chemicals that are not dyed but are oxidized to provide the desired color. As a result, the phrase "oxidative hair dye" was emerged. The precursor part and coupler part are the two main ingredients in formulations for oxidative hair dyes. Quinonediimine intermediates are momentary compounds that are generated when combined with hydrogen peroxide (developer). As a result, the coupler agent and these compounds interact to form the appropriate hair dye molecule. Notably, the entire dyeing process requires both an alkaline medium and an oxidizing agent, often hydrogen peroxide, to ensure that the staining agents reach the cuticle widely. This review's objective is to provide information about hair dye formulations and mechanisms of action as well as repairing damaged hair and new applications.

Incorporation of doxylamine and N-doxylamine-oxide in human hair and the impact of a permanent oxidative hair dye.

Knowledge of the drug incorporation in hair and impact of cosmetic treatments remains essential to correctly interpret forensic cases. The study shows the analysis of doxylamine and doxylamine-N-oxide and the evaluation of the relationship between dose and hair concentration and the impact of hair treatment (oxidative dying). The study included (A) three subjects participated to the study: a regular user (Subject 1) and two single-dose users (Subject 2, 1 single dose; and Subject 3, 2 single doses spaced 5 months apart). Subject 3 applied a permanent oxidative hair dying monthly. (B) A permanent oxidative hair dying was applied twice to the hair collected from Subject 2. (A) The average concentrations in head hair for doxylamine and its N-doxylamine-oxide, respectively, were as follows: Subject 1, 1825 pg/mg and 16 pg/mg; Subject 2, 182 and <limit of quantification (LOQ); and Subject 3, Strand 1 (1 month after last single dose]; 1st cm: 367 pg/mg and 22 pg/mg; 2nd cm: 664 pg/mg and 37 pg/mg; 3rd cm 108 pg/mg and 13 pg/mg; 4th cm 13 pg/mg and 7 pg/mg); Strand 2 (5 months after last single dose: <LOQ). (B) The oxidative hair dying increased the concentration of the metabolite from undetected <LOQ up to 79 pg/mg (n = 3, RSD 6%). The concentration of the parent drug decreased from 128 pg/mg to 40 pg/mg (n = 3, RSD 4%). This is the first time the incorporation of doxylamine and its metabolite was evaluated with adequate and controlled information concerning dose and timing of ingestion for the evaluation of their incorporation and the impact of a cosmetic treatment.

Frequency of PPD (Para-Phenylenediamine) Allergy in Hair Dye Users in Faisalabad

Objective: To evaluate the frequency of PPD allergic contact dermatitis in hair dye users in Faisalabad district. Study Design: Cross Sectional study. Place and Duration of Study: Dermatology Outpatient Department of District Headquarter Hospital, Faisalabad from 01-07-2018 to 31-12-2018. Methodology: A cross sectional study was carried out in Dermatology Outpatient Department and 135 patients were included. Male and female patients were included in this study with the age between Results: A total number of 135 patients were included in this study. Gendser distribution showed that there were 110 (81.5%) males and 25 (18.5%) females. The mean age of the patients was 38.04±4.96 years. The mean duration of hair dye use of the patients was 4±1.5 years. There were 92 (68.1%) patients between 30-40 years of age and 43 (31.9%) patients between 41-50 years of age. There were 80 (59.3%) patients between 3-4 years of duration of hair dye and 55 (40.7%) patients between 4-5 years of duration of hair dye. PPD allergic dermatitis was observed in 13 (9.6) patients. There was no association between gender (p=0.232), age (p=0.591) and duration of hair dye use (p=0.676) with respect to PPD allergic dermatitis. Conclusion: Para-phenylenediamineis the commonest cause of hair dye contact dermatitis. Patients can present with a variety of clinical manifestations, including severe reactions. Patch testing remains the gold standard method for confirming PPD allergy. Avoiding future contact with permanent and semi-permanent hair dyes is the standard preventative measure. Keywords: Allergy, Hair, Phenylenediamine, Para-Phenylenediamine.

Patch test results to extracts of synthetic garments in textile dye positive patients.

Disperse dyes (DDs) are the most prevalent causes of textile-related allergic contact dermatitis and are used for colouring synthetic textile materials based on fibres such as polyester, acrylic, acetate and polyamide. Eight DDs are included in a textile dye mix (TDM) 6.6% petrolatum (pet.) in the European baseline patch test series. The aim of this study was to patch test TDM 6.6% pet. positive individuals with the extracts of synthetic fibre clothes that do not contain any of the pure DDs present in the TDM 6.6% to study the reactivity pattern. Seventy-three TDM-positive former patients tested between 2012 and 2017 at the Department of Occupational and Environmental Dermatology in Malmö, Sweden were invited to join the study, 10 participated. Twenty-four textile items (collected in nine countries in Europe, Asia and North America in 2012) were extracted in dichloromethane. The TDM 6.6% was patch tested simultaneously with the 24 textile item preparations in petrolatum made from the extracts. Prior to patch testing the participants filled the 7-question questionnaire regarding possible symptoms from textile exposure. Ten individuals, agreed to join the study. Eight of them reacted to TDM 6.6%. Nine participants reacted to 20 of 24 extracts. One reacted to 19 extracts, another to 14, 3 to 5 extracts, 1 to 4, 1 to 3 extracts and 2 to 2 extracts. One was negative to all tested preparations including TDM 6.6%. The participants mainly reacted to six textile extracts. All controls tested negatively to tested extracts. Four individuals of the 10 TDM-allergic individuals previously had had problems after wearing clothes. Four out of the 10 participants had had atopic eczema in childhood. All women had dyed their hair with permanent hair dyes but none of the males. TDM-positive patients react to textile extracts made from synthetic garments, even if they do not contain any of the pure DDs present in TDM 6.6%. More studies are needed to pin-point the culprit haptens in these extracts.

A clinical evaluation of a permanent hair dye designed to reduce allergic contact dermatitis and hair damage.

Permanent hair dye is the most commonly used anti-aging procedure used by both men and women. However, permanent hair dye can cause irritant contact dermatitis due to ammonia and allergic contact dermatitis due to paraphylenediamine (PPD). This research examined an ammonia-free and PPD-free permanent hair dye in 50 ethnically diverse females 21-91 years of age who were current users of permanent hair dyes. Subjects were patch tested prior to dyeing. Two dye sessions were undertaken at baseline and 2-6 weeks post-baseline depending on the dyeing habits of the subject. 50/50 subjects successfully completed the study with no incidence of allergic or irritant contact dermatitis. After 2 dyeing procedures, the dermatologists rated an 87% improvement in hair shine, 90% improvement in hair color, 88% improvement in hair moisturization, 87% improvement in hair porosity, and 88% improvement in hair combability. A MEA-based ammonia-free cream hair color without PPD or resorcinol was safe for use on the hair and scalp of females with diverse hair types and textures.

Permanent Low-Toxicity Hair Dye Based on Pregrafting Melanin with Cystine.

A pregrafting strategy is presented to construct covalent bridges between synthetic melanin, i.e., polydopamine (PDA), and hair for permanent hair dyeing. As a result, PDA is more uniformly distributed throughout the hair surface, and the dyed hair shows higher color intensity and better durability to washing than the control samples dyed with PDA directly at the same conditions.

Superoxide anion radical induced phototoxicity of 2,4,5,6-Tetraminopyrimidine sulfate via mitochondrial-mediated apoptosis in human skin keratinocytes at ambient UVR exposure

2,4,5,6-Tetraaminopyrimidine sulfate (TAPS) is worldwide the most commonly used developer in hair dyes. As skin is the major organ, which is directly exposed to these permanent hair dyes, a comprehensive dermal safety assessment is needed. Hereto, we studied the photosensitization potential and mechanism involved in dermal phototoxicity of TAPS exposed to the dark and UVA/UVB/Sunlight by using different in-chemico and mammalian (HaCaT) cells, as test systems. Our experimental outcomes illustrate that TAPS get photodegraded (LC-MS/MS) and specifically generated superoxide anion radical (O2•−) under UVA and UVB via type-I photodynamic reaction. The phototoxic potential of TAPS is measured through MTT, NRU, and LDH assays that depicted a significant cell viability reduction at 25 μg/ml concentration and higher. Different cellular stainings (PI uptake, AO/EB, JC-1, NR uptake) suggested the role of mitochondrial-mediated apoptosis. Further, the transcriptomics study revealed upregulation of Apaf-1, Bax, Cytochrome c, Caspase 3, Caspase 9 and downregulation of Catalase and Bcl-2 by TAPS treated cells that strengthen our findings. Thus, the above findings suggest that chronic application of TAPS may be hazardous for human skin and promote various skin diseases.

Para-phenylenediamine deteriorates oocyte quality by impairing mitochondrial function.

Several studies demonstrate that para-phenylenediamine (PPD) is often added to permanent oxidative hair dyes. Sub-chronic topical exposure to PPD in male rats damages their testicular function; however, little is known about the effects of PPD exposure on the female reproductive system, especially on oocyte quality. In this study, we found that PPD can affect the meiotic capacity of oocytes and their fertilization potential. In particular, PPD can damage the spindle/chromosome structure and prevent oocytes from developing and maturing normally. Furthermore, PPD exposure compromised the dynamics of cortical granules and their component, ovastacin. In addition to the protein level of Juno, the sperm receptors on the egg membrane, were substantially impaired in PPD-administered oocytes, thus leading to fertilization failure. Finally, we found that PPD exposure resulted in abnormal mitochondrial function, which led to oocyte degeneration, apoptosis, and increased ROS levels. Altogether, our study illustrates that mitochondrial dysfunction and redox perturbation are the major causes of the poor quality of oocytes exposed to PPD.

“Gold Inlaid with Hair”: Permanent Fluorescent Hair Dyeing Using Fast Protein-Assisted Biomineralization of Gold Nanoclusters

Permanent fluorescent hair dyeing is one of the modern coloration modes to meet the increasing demands of personality and fashion statements. However, the limited durability and narrow Stokes shift of small molecule dyes hinder the permanent performance and distinguished use of fluorescent hair dyes from conventional hair coloration. Here, fluorescent metal nanomaterials, gold nanoclusters, have been utilized as hair dyes and embedded inside hair through a fast protein-assisted biomineralization approach under heating and alkaline conditions. Heat and alkalinity not only ensure that the scales of hair fully open and the dye precursor is deeply pervasive but also largely promote the reducibility of hair protein. The introduction of gold nanocluster bestows a broad range of new photophysical, much enhanced antistatic, mechanical, durable, and biocompatible properties to hair, largely improving the comfort experience and cosmetic performance.

Revealing the binding properties between resorcinol and DNA

Resorcinol (1,3-dihydroxybenzene) is a common coupling agent in permanent hair dyes, and has arrested people's attention for its potential hazard to human health. However, the action mechanism of resorcinol and human DNA has not been elucidated. In this research, the binding properties between resorcinol and calf thymus DNA (ct-DNA) were studied for the first time through various spectral and molecular docking techniques. Spectral studies showed that the initial fluorescence quenching of resorcinol against DNA was a static one. The result of ΔH < 0 and ΔS > 0 was produced from thermodynamic experimental data, therefore it could be concluded that electrostatic force was the major driving force, while binding constant Kb was 1.56 × 104 M-1 at 298 K. The electrostatic binding network between resorcinol and ct-DNA was established explicitly through competitive substitution analysis and other spectral approaches. The results of FT-IR absorption spectra indicated that resorcinol had bound to the DNA phosphate skeleton. Molecular docking clearly revealed that binding occurred between hydroxyl groups of resorcinol and phosphorus oxygen bonds (P-O) of the DNA skeleton. These findings may deepen our understanding of the action mechanism between resorcinol and ct-DNA and provide some useful data on the effect of resorcinol on human diseases.