US-12624473-B2 - DNA-programmed photonic crystal fabrication processes

US12624473B2US 12624473 B2US12624473 B2US 12624473B2US-12624473-B2

Abstract

A two-step process is provided for forming large photonic single crystals of about 0.1 millimeter and greater via DNA coated colloidal particles. The two-step process generally include decoupling the nucleation and growth steps. In particular, DNA colloidal particles are partitioned in nanoliter droplets formed in a water in oil emulsion using microfluidics. Once a crystal nucleates within a droplet, depletion of particles occurs as the crystal grows inhibit formation of more crystals within the droplet. A small number of droplets containing these seed crystals are then mixed with droplets containing weak DNA coated colloidal particles. The emulsion is then broken and heated at a temperature effective to cause dissociation of the weak particles while the seeds remain stable. The system is further cooled at a temperature effective that the particles stably adhere to the seed crystals resulting in growth while inhibiting nucleation of new crystals.

Inventors

William Benjamin Rogers
Alexander Hensley
William M. Jacobs

Assignees

BRANDEIS UNIVERSITY
THE TRUSTEES OF PRINCETON UNIVERSITY

Dates

Publication Date: 20260512
Application Date: 20231019

Claims (14)

1 . A two-step process for forming DNA programmed crystals via seeded growth, the two-step process comprising: a first step comprising nucleating single seed crystals in droplets formed in a water in oil emulsion by cooling the emulsion from above a melting temperature of the seed crystal to a nucleation temperature, wherein each of the monodisperse droplets comprise a binary suspension of DNA coated colloidal particles having a first grafting density of DNA; and a second step comprising growing the single seed crystals to form larger three-dimensional crystals by mixing a portion of the monodisperse droplets containing the single seed crystals with monodisperse droplets containing weakly DNA coated colloidal particles, wherein the weakly DNA coated colloidal particles have a second grafting density of DNA less than the first grafting density followed by breaking the emulsion to form a metastable colloidal suspension including the seed crystals, and annealing the metastable colloidal suspension at a temperature greater than the melting temperature of the weakly DNA coated particles and less than a melting temperature of the seed crystal to form the larger three-dimensional crystals, wherein growth of the seed crystals is diffusion limited, and wherein the melting temperature of the weakly DNA coated particles is greater than a nucleation temperature during the growing.
2 . The two-step process of claim 1 , wherein cooling the emulsion in the first step continues until all of the DNA coated colloidal particles in each monodisperse droplet are incorporated into the seed crystal.
3 . The two-step process of claim 1 , wherein breaking the emulsion comprises exposing the emulsion to an ionizer.
4 . The two-step process of claim 1 , wherein the DNA in the DNA coated particles and the weakly DNA coated particles comprise a sticky end portion having less than about 25 complementary nucleotides.
5 . The two-step process of claim 1 , wherein the DNA coated colloidal particles and the weakly comprise DNA functionalized polystyrene particles.
6 . The two-step process of claim 1 , wherein growing the single seed crystals to form larger three-dimensional crystals comprises attaching the particles in the metastable colloidal suspension to a crystal surface at a higher temperature than that at which nucleation occurs.
7 . The two-step process of claim 1 , wherein nucleating the single seed crystals continues until all of the DNA coated colloidal particles within the droplet are incorporated into the crystal phase.
8 . The two-step process of claim 1 , wherein the nucleating temperature is decreased in a staircase fashion at defined temperature intervals.
9 . The two-step process of claim 1 , wherein the ratio of droplets containing the single seed crystals to monodisperse droplets containing the weakly DNA coated colloidal particles is between about 0.1% to about 0.01%.
10 . The two-step process of claim 1 , wherein the water in oil emulsion is made by microfluidics.
11 . A process for growing macroscopic crystals, comprising: mixing droplets containing seed crystals formed from DNA coated colloidal particles with droplets containing weak DNA coated colloidal particles having a lower nucleation temperature than the droplets containing seed crystals from the DNA coated colloidal particles; breaking the emulsion to form a metastable DNA coated colloidal particle suspension including the seed crystals; annealing the mixture at a temperature above the nucleation temperature of the weak DNA coated particles but below a melting temperature of the seed crystals; and decreasing the temperature to grow larger crystals from the seed crystals with the weak DNA coated colloidal particles.
12 . The process according to claim 11 , wherein the larger crystals have a size within 10 percent of an average sized large crystal.
13 . The process according to claim 11 , wherein annealing the mixture at a temperature above a homogenous nucleation temperature of the weak DNA coated particles but below a melting temperature of the seed crystals lowers supersaturation.
14 . The process according to claim 11 , wherein decreasing the temperature comprises incremental decreases in a staircase fashion for a defined interval.

Description

CROSS REFERENCE TO RELATED APPLICATIONS The present application claims the benefit of U.S. Provisional Application No. 63/380,258, filed on Oct. 20, 2022, which is hereby incorporated herein by reference in its entirety. GOVERNMENT SUPPORT This invention was made with government support under DMR1710112 awarded by the National Science Foundation. The government has certain rights in the invention. SEQUENCE LISTING The Instant Application contains a Sequence Listing which has been submitted electronically in XML format and is hereby incorporated by reference in its entirety. Said XML copy, created on Jan. 18, 2024, is named “9F07961” and is 2,903 bytes in size. The Sequence Listing does not go beyond the disclosure in the application as filed. BACKGROUND The present disclosure generally relates to photonic crystals, and more specifically, processes for fabricating photonic crystals using DNA programmed interactions. Photonic crystals are optical metamaterials, meaning their optical properties are derived from not just their material composition but from the structure of the material itself. It has been shown that crystal lattices of spherical particles roughly the diameter of half the wavelength of visible light can reflect and transmit light in novel ways that haven't been achieved with uniformly solid bulk materials. Using programmable self-assembly of DNA-coated nano- and microparticles is a common way to self-assemble colloidal particles into ordered photonic structures and can even lead to colloidal crystals that are as of yet impossible to assemble any other way, such as colloidal diamond, which is predicted to exhibit a complete photonic bandgap of visible frequencies. To self-assemble these metamaterials from DNA-coated particles, most labs use a single step process that generally includes bulk nucleation and growth of the crystals. In these processes, the temperature of the system is raised until the particles disassociate, which is then lowered to a constant temperature where stochastic nucleation occurs. Then, the temperature is held until the nucleated crystals have grown. The temperature at which crystallization of DNA-coated colloidal particles occurs is slightly below the melting point of the particles (i.e., temperature at which the particles disaggregate) and requires careful temperature control because of the vastly different length scales between the nanometer-scale DNA molecules and the micrometer-scale colloidal particles, which leads to crystallization kinetics that are extremely sensitive to temperature and therefore prone to kinetic trapping. For example, recent work has shown that the crystal nucleation rates vary by orders of magnitude over a temperature range of only 0.25° C. As a result, it has proven difficult to assemble single crystalline materials using DNA programmed self-assembly that are larger than a few dozen micrometers in size. Instead, the larger self-assembled crystals are typically polycrystalline with heterogeneous domain sizes. Moreover, with many nuclei growing at random positions and times within the sample, these crystals compete for resources with each other or begin to cluster together into polycrystals that may not have uniform optical properties. This competition in crowding also tends to lead to a large spread in crystal size and limit the maximum size of the crystals to a few dozen micrometers, which limits the practical application of these materials. SUMMARY Embodiments of the present disclosure are generally directed to processes for forming the crystals from DNA coated colloidal particles. A non-limiting example process of fabricating a crystal from DNA coated colloids according to embodiments of the disclosure includes a two-step process including a first step of nucleating single seed crystals in droplets formed in a water in oil emulsion by cooling the emulsion from above a melting temperature of the seed crystal to a nucleation temperature, wherein each of the monodisperse droplets comprise a binary suspension of DNA coated colloidal particles having a first grafting density of DNA; and a second step of growing the single seed crystals to form larger three-dimensional crystals by mixing a portion of the monodisperse droplets containing the single seed crystals with monodisperse droplets containing weakly DNA coated colloidal particles, wherein the weakly DNA coated colloidal particles have a second grafting density of DNA less than the first grafting density followed by breaking the emulsion to form a metastable colloidal suspension including the seed crystals, and annealing the metastable colloidal suspension at a temperature greater than the melting temperature of the weakly DNA coated particles and less than a melting temperature of the seed crystal to form the larger three-dimensional crystals, wherein growth of the seed crystals is diffusion limited, and wherein the melting temperature of the weakly DNA coated particles is greater than a nucle